Thursday, June 23, 2016

Full-scale Disneyland (with canals!), and sustainability issues

We recently returned from a 2-week trip to Italy.  Two of our children and their spouses live in Europe.  One couple lives in a small town in northern Italy, the other in central Switzerland.  The latter drove down to Italy where we all enjoyed seeing each other, which is not easy given the distances.  But while this vacation/family gathering was very pleasant and, to us, important, it raises some less pleasant thoughts about sustainability in our time in history.

My concerns are personal, but in a sense also global, and to some extent they relate to societal inequity: not everybody can just drop a few thou and travel across the ocean for a couple of weeks' dinners with family.  But beyond unfairness, my concerns are about other issues.  This was a very energy-bad vacation, and we weren't alone!

We flew from the east coast to Venice, the most convenient airport for our purposes.  We flew on a large plane, maybe 2/3 full of passengers. As we all know, one of the worst ways to contribute to global warming is to fly. The aircraft was largely filled with people taking cruises in the Mediterranean.  The trip was about 3700 miles each way, not including the various train and car junkets we took during those two weeks.

And then there's Venice itself.  We stayed a couple of days there to recover from jet lag, and to see the sites.  We'd been there for a science meeting once before.  Bella Venezia!  Once home to a world-leading trade empire, and to many great cultural and architectural wonders and of course its romantic lacework of canals.  The glory days were then, but what is the city today?  Venice takes in something like 100,000 tourists a day, well more than the number of people who actually live there.  The piazzas, side streets, walkways, and bridges--and they are very scenic indeed--are often a shoulder-to-shoulder river of tourists.  They (and we) sightsee in museums, shop, eat, shop, stay in hotels, eat, and shop.  It is obvious that a huge amount of money pours into the city, every day, all year, and has been doing so for decades if not centuries.

Even forgetting their thought-provoking historical value and more trivial entertainment value, and just thinking of them as Disneyesque curiosities for selfie-ops, these museums, shops, and hotels are staffed by an army of people who earn their living from the tourist trade.  So while Venice is in a sense unique and beautiful, it is also in a perhaps deeper sense something of a fake, a touristic Potemkin village, a hyper, full-time, full-scale Disneyland entertainment park, there today mainly to pluck the pockets of the relatively idle affluent and wasteful denizens of our planet (I certainly include myself in that category!).

St Mark's Square, Venice; By Nino Barbieri - Own work

Venice is but one rather small city on the global tourist map.  If you think about the amount of fuel used to transport everyone to, from, and around Venice (and even take into account that the gondolas don't require fossil fuel!), and then multiply that by the hundreds of tourist sites around the world, you have to wonder what hope there is for containing global warming.  There is no sign of self-restraint of any kind here--even on departure to return home, the airport luxury shops do a booming business as tourists part with whatever dollars they've not yet spent.

But what can one seriously do?
It is easy to chastise people who take such totally needless trips, even if accompanied by a self-incorporating mea culpa.  After all, this really is a nearly total luxury.  For most of human history those relatives who moved or sailed far away never saw their family again and corresponded by mail (if at all, if there was such a thing as 'mail').  That was just how life was!  Our family get-togethers are a new, pure luxury.  In a seriously conservation-dedicated world, we could dispense at least with the purely sightseeing, self-indulging kinds of global vacationing.  That would seem like something trivial, a luxury that a resource-conscious world could easily forego.  But even if we all were so equitable, fair, future-aware, and so on, things aren't nearly so simple.

The world is crowded with people and much of it is industrialized, with the number of people who live on the land, as subsistence farmers, declining every year.  We have hugely diverse economies, in a sense creating occupations that earn money so we can swap that for food and so on.  Most of it isn't really necessary.  Among these non-food related activities is tourism, which is huge because so many people are now wealthy and idle enough to take global junkets.

In turn that means that much of the world depends on travel and sightseeing.  Countless peoples' livelihoods are involved.  This is in a sense quite antithetical to global sustainability.  If we seriously slowed down travel to save fossil fuels and reduce warming, then tourism, air travel, cruise ships, and the people involved in the manufacture and operation of planes, ships, trains and buses, their ports and terminals, would lose their jobs. The manufacturers of tourist-related goods, including Venetian carnival masks, post-cards, luxury shopping goods, hotel supplies, restaurant foods, chefs, waiters, menu printers, clerks, etc. would be hit.  Venice, already a shell of its former self, would cease to have a reason to exist.  Even those who deliver all these goods during the night, and those who remove the trash, invisible to the tourists sleeping quietly in their beds, would be affected.  Society would somehow have to do something about their employment needs.  

This means that the idea of just paring back on consumption really is a dream--or, as every even mild economic depression shows, a nightmare.  And just the one example of tourism, essentially a luxury trade, involves countless thousands of people.  Needless to say, all of this is grossly unfair to the huge majority of people living on or below the margins.  It shows the inadvertent implications, even the distanced cruelty, of those idealists who want quick changes in sustainability directions.

It is difficult to have a non-selfish moral position on these issues.  If we say "let's change things slowly so as not to be too disruptive to too many people", the normal human tendency is to think the problem isn't so real, and not even go along with 'slowly' with much dedication. That's why car companies begin making and hawking, and consumers purchasing, bigger cars and trucks the moment gas prices drop.  [I insert this post-posting editorial change because today's NY Times had a story about the return of gas-guzzlers, in the same spirit of what this post is about]

If we say 'we must rush' then too many will find rationales for not going along ('OK, it's a good idea, but I can't do it--I have to see my family overseas!').  So where is a feasible ground to be found, and to what extent should we personally expect to be affected by it?  What will we give up for the cause?  The question, for me, is not abstractly how much one must cut out of what one does, but how much I must cut!  That gets pretty close to home, so to speak.

I can't help but add a rather gratuitous, if snide, side comment. The problems are compounded in an ironic way.  We have agricultural sustainability issues, as everyone by now should know.  The 'developed' world suffers common diseases largely due to bad nutrition and that means to over-eating. So while much of the world barely scrapes by, many in the rich world waddle along largely over-weight (these are not the minority of people struggling with genetic or epigenetic problems that make weight control a real challenge).  The obesity epidemic is why we hear complaints about airplane seats being too small!  So I remark snarkily that, as a consequence, one reason air travel is so environmentally unfriendly is the countless tons of human bulk that are being transported daily across the oceans in tourist-filled aircraft.  One thing leads to another.

We just took what was clearly a very energy-bad trip, no matter how understandable our desire to be with family and our decision to go.  We could, of course, have talked with our family members via Skype--indeed, we already do that often.  I complain that leaders in sustainability and climate change, including the very organization that documents it for the UN, fly all over the world and meet in fancy hotels to discuss the problem and tell everyone what they (that is, they) must do to 'save the planet'. The leading spokespersons for sustainability and climate-change avoidance could set a very public example and work only via Skype! 

In the context of global conservation, sustainability, and climate issues, who should feel guilty about what?  If do as I say not as I do is not acceptable, then what justifies our personal exceptionalism? For me, the answers are far from clear.

Tuesday, May 31, 2016

Genes: convenient tokens of our time

My post today, perhaps typically cranky, was triggered by an essay at Aeon about the influence that the film Still Alice has had on thinking about Alzheimer's Disease (AD). As the piece puts it, AD is presented in the film as a genetic disease with a simply predictable doom-like known genetic cause.  The authors argue that the movie is more than entertainment.  It's a portrayal that raises an important ethical issue, because it is very misleading to leave the impression that AD is a predictable genetic disease.  That's because a clear genetic causation, and thus the simple 'we can test for it' representation, applies only to a small fraction of AD.  The film badly misrepresents the overall reality of this awful form of the disease (a good treatment of Alzheimer's disease and its history is Margaret Lock's thoughtful The Alzheimer Conundrum, 2013, Princeton Press).

While focusing on AD, the Aeon piece makes strong statements about our obsession with genes, in ways that we think can be readily generalized.  In a nutshell, genes have become the convenient tokens of our time.

Symboling is a key to making us 'human'
If there is any one thing that most distinguishes our human species from others, it may be the use of language as a symbolic way to perceive the world and communicate to others.  Symboling has long been said by anthropologists to be an important key to our evolution and the development of culture, itself based on language.

Symbol and metaphor are used not just to represent the world and to communicate about it, but also to sort out our social structure and our relationships with each other and the world.  Language is largely the manipulation or invocation of symbols.  In a species that understands future events and generalities, like death and sex, in abstract terms, the symbols of language can be reassuring or starkly threatening.  We can use them to soothe ourselves or to manipulate others, and they can also be used in the societal dance around who has power, influence, and resources.

Symbols represent a perception of reality, but a symbol is not in itself reality.  It is our filter, on or around which we base our interactions and even our material lives.  And, science is as thoroughly influenced by symbols as any other human endeavor.

Science is, like religion, a part of our culture that purports to lead us to understand and generalize about the world, but because science is itself a cultural endeavor, it is also part and parcel of the hierarchy and empire building we do in general, part of a cultural machinery that includes self-promotion, and mutually reinforcing service industries including news media, and even scientific journals themselves.

The current or even growing pressures to maintain factory-like 'productivity' in terms of grants coming in and papers going out is largely at odds with the fundamental purpose of science (as opposed to 'technology').  Unlike designing a better product, in the important, leading-edge areas of science, we don't know where we're going.  That is indeed the reason that it is science.  Exploring the unknown is what really good science is about.  That's not naturally an assembly-line process, because the latter depends on using known facts.  However, our society is increasingly forcing science to be like a factory, with a rather short-term kind of fiscal accountability.

Our culture, like any culture, creates symbols to use as tokens as we go about our lives.  Tokens are reassuring or explanatory symbols, and we naturally use them in the manipulations for various resources that culture is often about.  Nowadays, a central token is the gene.

DNA; Wikipedia

Genes as symbols
Genes are proffered as the irrefutable ubiquitous cause of things, the salvation, the explanation, in ways rather similar to the way God and miracles are proffered by religion.  Genes conveniently lead to manipulation by technology, and technology sells in our industrial culture. Genes are specific rather than vague, are enumerable, can be seen as real core 'data' to explain the world.  Genes are widely used as ultimate blameworthy causes, responsible for disease which comes to be defined as what happens when genes go 'wrong'.  Being literally unseen, like angels, genes can take on an aura of pervasive power and mystery.  The incantation by scientists is that if we can only be enabled to find them we can even cure them (with CRISPR or some other promised panacea), exorcising their evil. All of this invocation of fundamental causal tokens is particulate enough to be marketable for grants and research proposals, great for publishing in journals and for news media to gawk at in wonder. Genes provide impressively mysterious tokens for scientists to promise almost to create miracles by manipulating.  Genes stand for life's Book of Truth, much as sacred texts have traditionally done and, for many, still do.

Genes provide fundamental symbolic tokens in theories of life--its essence, its evolution, of human behavior, of good and evil traits, of atoms of causation from which everything follows. They lurk in the background, responsible for all good and evil.  So in our age in human history, it is not surprising that reports of finding genes 'for' this or that have unbelievable explanatory panache.  It's not a trivial aspect of this symbolic role that people (including scientists) have to take others' word for what they claim as insights.

This token does, of course, have underlying reality
We're in the age of science, so that it is only to be expected that we'll have tokens relevant to this endeavor.  That we have our symbols around which to build other aspects of our culture doesn't mean that the biology of genes is being made up out of whole cloth.  Unlike religion, where things can be 'verified' only by claims of communication with God, genes can of course, at least in principle, be checked and claims tested.  Genes obviously do have major and fundamental roles in life.  If that isn't true, we are really misperceiving fundamentals of our existence.  So, even when complexities of causation are daunting, we can claim and blame what we want on genes and in a sense be correct at least at some level.  That enhances and endorses the token value of genes.

Genes do have great sticking power.  The Aeon piece about AD is just one of countless daily examples.  A fraction of cases of AD are so closely associated with the presence of some known variants in a couple of genes, that true causation--whatever the mechanism--seems an entirely plausible explanation.  Likewise, there are hundreds or thousands of disorders that seem clearly to be inherited and as the result of malfunction of one or two specific genes.  The cultural extension of this in our society that we are stressing here is the extension of these clearly causative findings to the idea that causation can be enumerated in convenient ways mainly by peoples' inherited genomes and that other aspects of biological causation are often treated as being rather superficial or incidental.  That in a sense is typical of deeply held cultural icons or tokens.

The problem with genes as tokens is that they are invoked generally or generically in the competition for cultural resources, material and symbolic.  Personally, we think there are issues, genetic issues in fact, that deserve greater investment, rather than just the easier to invoke bigger-is-better approach. They include a much more intense attack on those many traits that we already know without any serious doubt are tractably genetic--due to one or only a couple of genes, and therefore which real genetic therapy might treat or prevent effectively.  By contrast, most traits even if they are affected by genetic variation as all traits must be, are predominantly due to environmental or chance causative factors.  We have ways to avoid many diseases that don't require genetic approaches, but as vague entities they're perfect subjects for invoking the gene token, and policy in the industrial world clearly shows this.

Some progress does of course occur because of genetically-based research, but the promise far outpaces the reality of genetic cures.  But genes are the material tokens that keep the motor running far beyond the actual level of progress.  They effectively reflect our time--our molecular, computer, technological culture imagery, our love of scale, size and the material grandeur they generate.

Every culture, every generation has its tokens and belief systems.  Genes are among ours.  They're never perfect.  People seek hope, and what velvet robes and gilded cathedrals and mosques provide for many, whereas the humming laboratories do for a growing number of others.

Tokens, symbols and metaphors: they drive much of what people do, even in science.

Monday, May 30, 2016

Cancer moonshot and slow-learners

Motivated by Vice President Biden's son's death at an early age from cancer, President Obama recently announced a new health initiative which he's calling the cancer 'moonshot'.  This is like a second Nixonian 'war' on cancer but using a seemingly more benign metaphor (though cancer is so awful that treating it as a 'war' seems apt in that sense). Last week the NYTimes printed an op-ed piece that pointed out one of the major issues and illusions belied by the rhetoric of the new attack on cancer, as with the old:  Curing one cancer may extend a person's life, but it also increases his or her chances of a second cancer, since risks of cancer rise with age.

Cancers 'compete' with each other for our lives
The op-ed's main point is that the more earlier onset cancers we cure, the more late onset, less tractable tumors we'll see.  In that sense, cancers 'compete' with each other for our lives.  The first occurrence would get us unless the medical establishment stops it, thus opening the door for some subsequent Rogue Cell to generate a new tumor at some later time in the person's life.  It is entirely right and appropriate in every way to point this out, but the issues are subtle (though not at all secret).

First, the risk of some cancers slows with age.  Under normal environmental conditions, cancers increase in frequency with age because they are generally due to the accumulation of multiple mutations of various sorts, so that the more cell-years of exposure the more mutations that will arise.  At some point, one of our billions of cells acquires a set of mutational changes that lead it to stop obeying the rules of restraint in form and cell-division that are appropriate for the normal function of its particular tissue. A tumor is a combination of exposure to mutagens and mutations that occur simply by DNA replication errors--totally chance events--when cells divide.  As the tumor grows it acquires further mutations that lead it to spread or resist chemotherapy etc.

This is important but the reasons are subtle.  The attack on cells by lifestyle-related mutagens like radiation or chemicals in the environment becomes reduced in intensity as people age and simplify their lives, slowing down a lot of exposures to these risk factors. However, cell division rates, the times when mutations arise, themselves slow down, so the rate of accumulation of new mutations, whether they be by chance or by exposures, slows.  This decrease in the increase of risk with age at least tempers the caution that curing cancers in adults will leave them alive for many years and hence at risk for at least some many more cancers (though surely it will make them vulnerable to some!)

Apollo 11, first rocket to land humans on the moon; Wikipedia

Competing causes: more to the story, but nothing at all new
There's an important issue not mentioned in the article, but that is much more important in an indirect way.  This is an issue the authors of the op-ed didn't think about or for some reason didn't mention or perhaps because they are specialists they just weren't aware of.  But it's not at all secret, and indeed is something we ourselves studied for many years, and we've blogged about here before: anything that reduces early onset diseases increases the number of late onset diseases.  So, curing cancer early on (which is what the op-ed was about) increases risk for every later-onset disease, not just cancer.  In the same way as we've noted before, reducing heart disease or auto accident rates or snake bite deaths will increase dementia, heart disease, diabetes, and cancer--all other later-onset diseases--simply because more people will live to be at risk.  This is the Catch-22 of biomedical intervention.

In this sense all the marketing rhetoric about 'precision' genomic medicine is playing a game with the public, and the game is for money--research money among other things.  There's no cure for mortality or the reality of aging.  Whether due to genetic variants or lifestyle, we are at increasing risk for the panoply of diseases as we age, simply because exposure durations increase.  And every victory of medicine at earlier ages is a defeat for late-age experience.  Even were we to suppose that massive CRISPRization could cure every disease as it arose, and people's functions didn't diminish with age, the world would be so massively overpopulated as to make ghastly science fiction movies seem like Bugs Bunny cartoons.

But the conundrum is that because of the obvious and understandable fact that nobody wants major early onset diseases, it seems wholly reasonable to attack them with all the research and therapeutic vigor at our disposal. The earlier and more severe, the greater the gain in satisfactory life-years that will be made.  But the huge investment that NIH and their universities clients make in genomics and you-name-it related to late-age diseases is almost sure to backfire in these ways.  Cancer is but one example.

People should be aware of these things.  The statistical aspects of competing causes have long been part of demographic and public health theory.  Even early in the computer era many leading demographers were working on the quantitative implications of competing causes of death and disease, and similar points were very clear at the time.  The relevance to cancer, as outlined above, was also obvious.  I know this first-hand, because I was involved in this myself early in my career.  It was an important part of theorizing, superficial as well as thoughtful, about the nature of aging and species-specific lifespan, and much else.  The hard realities of competing causes have been part of the actuarial field since, well, more or less since the actuarial field began.  It is a sober lesson that apparently nobody wants to hear.  So it should not be written about as if it were a surprise, or a new discovery or realization.  Instead, the question--and it is in every way a fair question--should be why we cannot digest this lesson.  Is it because of our normal human frailty wishful thinking about death and disease, or because it is not convenient for the biomedical industries to recognize this sober reality front and center?

It's hard to accept mortality and that life is finite.  Some people want to live as long as possible, no matter the state of their health, and will reach for any life-raft at any age when we're ill.  But a growing number are signing Do Not Resuscitate documents, and the hospice movement, to aid those with terminal conditions who want to die in peace rather than wired to a hospital bed, continues to grow.  None of us wants a society like that in Anthony Trollope's 1881 dystopic novel The Fixed Period, where at age 67 everyone is given a nice comfortable exit--at least that was the policy until it hit too close to home for those who legislated it.  But we don't want uncomforable, slow deaths, either.

The problem of competing causes is a serious but subtle one, but health policy should reflect the realities of life, and of death.  I wouldn't bet on it, however, because there is nothing to suggest that humans as a collective electorate are ready or able to face up to the facts, when golden promises are being made by legislators, bureaucrats, pharmas, and so on.  But, science and scientists should be devoted to truth, even when truth isn't convenient to their interests or for the public to hear.

Thursday, May 19, 2016

Another look at 'complexity'

A fascinating and clear description of one contemporary problem of sciences involved in 'complexity' can be found in an excellent discussion of how brains work, in yesterday's Aeon Magazine essay ("The Empty Brain," by Robert Epstein).  Or rather, of how brains don't work.  Despite the ubiquity of the metaphor, brains are not computers.  Newborn babies, Epstein says, are born with brains that can learn, respond to the environment and change as they grow.
But here is what we are not born with: information, data, rules, software, knowledge, lexicons, representations, algorithms, programs, models, memories, images, processors, subroutines, encoders, decoders, symbols, or buffers – design elements that allow digital computers to behave somewhat intelligently. Not only are we not born with such things, we also don’t develop them – ever.
We are absolutely unqualified to discuss or even comment on the details or the neurobiology discussed.  Indeed, even the author himself doesn't provide any sort of explanation of how brains actually work, using general hand-waving terms that are almost tautologically true, as when he says that experiences 'change' the brains.  This involves countless neural connections (it must, since what else is there in the brain that is relevant?), and would be entirely different in two different people.

In dismissing the computer metaphor as a fad based on current culture, which seems like a very apt critique, he substitutes vague reasons without giving a better explanation.  So, if we don't somehow 'store' an image of things in some 'place' in the brain, somehow we obviously do retain abilities to recall it.  If the data-processing imagery is misleading, what else could there be?

We have no idea!  But one important thing is that this essay reveals is that the problem of understanding multiple-component phenomena is a general one.  The issues with the brain seem essentially the same as the issues in genomics, that we write about all the time, in which causation of the 'same' trait in different people is not due to the same causal factors (and we are struggling to figure out what they are in the first place).

A human brain, but what is it?  Wikipedia

In some fields like physics, chemistry, and cosmology, each item of a given kind, like an electron or a field or photon or mass is identical and their interactions replicable (if current understanding is correct).  Complexities like the interactions or curves of motion among many galaxies each with many stars, planets, and interstellar material and energy, the computational and mathematical details are far too intricate and extensive for simple solutions.  So one has to break the pattern down into subsets and simulate them on a computer.  This seems to work well, however, and the reason is that the laws of behavior in physics apply equally to every object or component.

Biology is comprised of molecules and at their level of course the same must be true.  But at anything close to the level of our needs for understanding, replicability is often very weak, except in the general sense that each person is 'more or less' alike in its physiology, neural structures, and so on. But at the level of underlying causation, we know that we're generally each different, often in ways that are important.  This applies to normal development, health and even to behavior.  Evolution works by screening differences, because that's how new species and adaptations and so on arise.  So it is difference that is fundamental to us, and part of that is that each individual with the 'same' trait has it for different reasons.  They may be nearly the same or very different--we have no a priori way to know, no general theory that is of much use in predicting, and we should stop pouring resources into projects to nibble away at tiny details, a convenient distraction from the hard thinking that we should be doing (as well as addressing many clearly tractable problems in genetics and behavior, where causal factors are strong, and well-known).

What are the issues?
There are several issues here and it's important to ask how we might think about them.  Our current scientific legacy has us trying to identify fundamental causal units, and then to show how they 'add up' to produce the trait we are interested in.  Add up means they act independently and each may, in a given individual, have its own particular strength (for example, variants at multiple contributing genes, with each person carrying a unique set of variants, and the variants having some specifiable independent effect).  When one speaks of 'interactions' in this context, what is usually meant is that (usually) two factors combine beyond just adding up.  The classical example within a given gene is 'dominance', in which the effect of the Aa genotype is not just the sum of the A and the a effects.  Statistical methods allow for two-way interactions in roughly this way, by including terms like zAXB (some quantitative coefficient times the A and the B state in the individual), assuming that this is the same in every A-B instance (z is constant).

This is very generic (not based on any theory of how these factors interact), but for general inference that they do act in relevant ways, it seems fine.  Theories of causality invoke such patterns as paths of factor interaction, but they almost always assume various clearly relevant simplifications:  that interactions are only pair-wise, that there is no looping (the presence of A and B set up the effect, but A and B don't keep interacting in ways that might change that and there's no feedback from other factors), that the size of effects are fixed rather than being different in each individual context.

For discovery purposes this may be fine in many multivariate situations, and that's what the statistical package industry is about. But the assumptions may not be accurate and/or the number and complexity of interactions too great to be usefully inferred in practical data--too many interactions for achievable sample sizes, their parameters being affected by unmeasured variables, their individual effects too small to reach statistical 'significance' but in aggregate accounting for the bulk of effects, and so on.

These are not newly discovered issues, but often they can only be found by looking under the rug, where they've been conveniently swept because our statistical industry doesn't and cannot adequately deal with them.  This is not a fault of the statistics except in the sense that they are not modeling things accurately enough, and in really complex situations, which seem to be the rule rather than the exception, it is simply not an appropriate way to make inferences.

We need, or should seek, something different.  But what?
Finding better approaches is not easy, because we don't know what form they should take.  Can we just tweak what we have, or are we asking the wrong sorts of questions for the methods we know about?  Are our notions of causality somehow fundamentally inadequate?  We don't know the answers.  But what we now do have is a knowledge of the causal landscape that we face.  It tells us that enumerative approaches are what we know how to do, but what we also know are not an optimal way to achieve understanding.  The Aeon essay describes yet another such situation, so we know that we face the same sort of problem, which we call 'complexity' as a not very helpful catchword, in many areas.  Modern science has shown this to us.  Now we need to use appropriate science to figure it out.

Monday, May 16, 2016

What do rising mortality rates tell us?

When I was a student at a school of public health in the late '70s, the focus was on chronic disease. This was when the health and disease establishment was full of the hubris of thinking they'd conquered infectious disease in the industrialized world, and that it was now heart disease, cancer and stroke that they had to figure out how to control.  Even genetics at the time was confined to a few 'Mendelian' (single gene) diseases, mainly rare and pediatric, and few even of these genes had been identified.

My field was Population Studies -- basically the demography of who gets sick and why, often with an emphasis on "SES" or socioeconomic status.  That is, the effect of education, income and occupation on health and disease.  My Master's thesis was on socioeconomic differentials in infant mortality, and my dissertation was a piece of a large study of the causes of death in the whole population of Laredo, Texas over 150 years, with a focus on cancers.  Death rates in the US, and the industrialized world in general were decreasing, even if ethnic and economic differentials in mortality persisted.

So, I was especially interested in the latest episode of the BBC Radio 4 program The Inquiry, "What's killing white American women?" Used to increasing life expectancy in all segments of the population for decades, when researchers noted that mortality rates were actually rising among lower educated, middle-aged American women, they paid close attention.

A study published in PNAS in the fall of 2015 by two economists was the first to note that mortality in this segment of the population, among men and women, was rising enough to affect morality rates among middle-aged white Americans in general.  Mortality among African American non-Hispanics and Hispanics continued to fall.  If death rates had remained at 1998 rates or continued to decline among white Americans who hadn't more than a high school education in this age group, half a million deaths would have been avoided, which is more, says the study, than died in the AIDS epidemic through the middle of 2015.

What's going on?  The authors write, "Concurrent declines in self-reported health, mental health, and ability to work, increased reports of pain, and deteriorating measures of liver function all point to increasing midlife distress."  But how does this lead to death?  The most significant causes of mortality are "drug and alcohol poisonings, suicide, and chronic liver diseases and cirrhosis."  Causes associated with pain and distress.

Source: The New York Times

The Inquiry radio program examines in more detail why this group of Americans, and women in particularly, are suffering disproportionately.  Women, they say, have been turning to riskier behaviors, drinking, drug addiction and smoking, at a higher rate than men.  And, half of the increase in mortality is due to drugs, including prescription drugs, opioids in particular.  Here they zero in on the history of opiod use during the last 10 years, a history that shows in stark relief that the effect of economic pressures on health and disease aren't due only to the income or occupation of the target or study population.

Opioids, prescribed as painkillers for the relief of moderate to severe pain, have been in clinical use since the early 1900's.  Until the late 1990's they were used only very briefly after major surgery or for patients with terminal illnesses, because the risk of addiction or overdose was considered too great for others.  In the 1990's, however, Purdue Pharma, the maker of the pain killer Oxycontin, began to lobby heavily for expanded use.  They convinced the powers-that-be that chronic pain was a widespread and serious enough problem that opioids should and could be safely used by far more patients than traditionally accepted.  (See this story for a description of how advertising and clever salesmanship pushed Oxycontin onto center stage.)

Purdue lobbying lead to pain being classified as a 'vital sign', which is why any time you go into your doctor's office now you're asked whether you're suffering any pain.  Hospital funding became partially dependent on screening for and reducing pain scores in their patients.

Ten to twelve million Americans now take opioids chronically for pain.  Between 1999 and 2014, 250,000 Americans died of opioid overdose.  According to The Inquiry, that's more than the number killed in motor vehicle accident or by guns.  And it goes a long way toward explaining rising mortality rates among working-class middle-aged Americans.  And note that the rising mortality rate has nothing to do with genes.  It's basically the unforeseen consequences of greed.

Opioids are money-makers themselves, of course (see this Forbes story about the family behind Purdue Pharma, headlined "The OxyContin Clan: The $14 Billion Newcomer to Forbes 2015 List of Richest U.S. Families;" the drug has earned Purdue $35 billion since 1995) but pharmaceutical companies also make money selling drugs to treat the side effects of opioids; nausea, vomiting, drowsiness, constipation, and more.  Purdue just lost its fight against allowing generic versions of Oxycontin on the market, which means both that cheaper versions of the drug will be available, and that other pharmaceutical companies will have a vested interest in expanding its use.  Indeed, Purdue just won approval for use of the drug in 11-17 year olds.

In a rather perverse way, race plays a role in this epidemic, too, in this case a (statistically) protective one even though it has its roots in racial stereotyping.  Many physicians are less willing to prescribe opioids for African American or Hispanic patients because they fear the patient will become addicted, or that he or she will sell the drugs on the street.

"Social epidemiology" is a fairly new branch of the field, and it's based on the idea that there are social determinants of health beyond the usual individual-level measures of income, education and occupation.  Beyond socioeconomic status, to determinants measurable on the population-level instead; location, availability of healthy foods, medical care, child care, jobs, pollution levels, levels of neighborhood violence, and much more.

Obviously the opioid story reminds us that profit motive is another factor that needs to be added to the causal mix.  Big Tobacco already taught us that profit can readily trump public health, and it's true of Big Pharma and opioids as well.  Having insinuated themselves into hospitals, clinics and doctors' offices, Big Pharma may have relieved a lot of pain, but at great cost to public health.

Wednesday, May 11, 2016

Darwin the Newtonian. Part V. A spectrum, not a dogma

Our previous installments on genetic drift (a form of chance) vs natural selection (a deterministic force-like phenomenon) and the degree to which evolution is due to each (part 1 here) lead to a few questions that we thought we'd address to end this series.

First, there is no sense in which we are suggesting that complex traits arise out of nowhere, by 'chance' alone.  There is no sense in which we are suggesting that screening for viability or utility does not occur as a regular part of evolution.  But we are asking what the nature of that screening is, and what a basically deterministic, Newtonian view of natural selection, that is we believe widely if often tacitly held, implies and how accurate it may be.

It's also important here to point out something that is obvious.  The dynamics of evolution from both trait and genome level comprise a spectrum of processes, not a single one that should be taken as dogma.  A spectrum means that there is a range of relative roles of what can be viewed as determinism and chance that the two are not as distinct as may seem, and that even identifying, much less proving what is going on in a given situation is often dicey.  Some instances of strong selection, like some of chance seem reasonably clear and those concepts are apt.  But much, perhaps most, of evolution is a more subtle mix of phenomena and that is what we are concerned with.

Secondly, we have discussed our view of natural selection before, in various ways.  In particular, we cite our series on what we called the 'mythology' of selection, a term we used to be provocative in the sense of hopefully stimulating readers to think about what many seem to take for granted.  Yes, we're repeating ourselves some, but think the issues are important and our ideas haven't been refuted in any serious way so we think they're worth repeating.

A friend and former collaborator took exception to our assumption that people still believe that what we see today is what was the case in the past.  He felt we were setting up a straw man. The answer is somewhat subjective, but we believe that if you read many, many descriptions of current function and their evolution, you'll see that they are often if not usually just equated de facto with being 'adaptations', and that means that doing what they do now came about because it was favored by the force of selection in the past.  We think it's not a straw man at all, but a description of what is being said by many people much of the time: very superficial, dogmatic assumptions both of determinative selection and that we can infer the functional reason.

Of course everyone acknowledges that earlier states had their own functions and today's came from earlier, and that functions change (bat wings used to be forelegs, e.g.), but the idea is that bat flight is here because the way bats fly was selected for.  One common metaphor going back to an article by Lewontin and Gould is that evolution works via 'spandrels', traits evolved for one purpose or incidentally part of some adaptation, that are then usable by evolution to serve some new function. Yes, evolution works through changing traits, but how often are they 'steps' in this sense or is the process more like a rather erratic escalator, if we need a metaphor?

There are ways for adaptive traits to arise that have nothing to do with Darwinian competition for limited resources, and are perfectly compatible with a materialist view.  Organismal selection occurs when organisms who 'like' a particular part of their environment, tend to hang out there.  They'll meet and mate with others who are there as well.  If the choice has to do with their traits--ability to function at high altitude, or whatever--then over time this trait will become more common in this niche compared to their peers elsewhere, and eventually mating barriers may arise, and a new species with what appears to be a selected adaptation. But no differential reproduction is required--no natural selection.  It's natural assortment instead.

All aspects of our structure and function depend on interaction among molecules.  If two molecules must interact for some function to occur, then mutant versions may not serve that purpose and the organism may perish. This would seem most important during embryonic development.  An individual with incompatible molecular interactions (due to genetic mutation) would simply not survive.  This leaves the population with those whose molecules do interact, but there is no competition involved--no natural selection.  It's natural screening instead.

Natural selection of the good ol' Darwinian kind can occur, leading to complex adaptations in just the way Darwin said 150+ years ago.  But if the trait is the result of very many genes, the individual variants that contribute may be invisible to selection, and hence come and go essentially by chance. This is what we have called phenogenetic drift.  Do you doubt that?  If so, then why is it that most complex traits that are mapped can take on similar values in individuals with very different genotypes?  This is, if anything, the main bottom line finding of countless very large and extensive mapping studies, in humans and even bacteria.  This is basically what Andreas Wagner's work, that we referred to earlier in the series, is about.   It rather obviously implies that which of equivalent variants proliferates is the result of chance.  There's nothing non-Darwinian about this.  It's just what you'd expect instead.

We'd expect this because the many factors with which any species must deal will challenge each of its biological systems. That means many screening factors (better we think than calling them selection 'pressures' as would usually be done).  Most of these are affected by multiple genes.  Genes vary within a population.  If any given factor's effects were too strong, it would threaten the species' existence.  At least, most must be relatively weak at any given time, even if persisting over very long time periods.  Multiple traits, multiple contributing genes in this situation means that relative to any one trait or gene, the screening must be rather weak.  That in turn means that chance affects which variant proliferates.  There's nothing non-Darwinian about this.  It's essentially why he stressed the glacial slowness of evolution.

There is, however, the obvious fact that known functional parts of DNA are far less variable than regions with no known function.  This can be, and usually is assumed to be, the expected evidence of Darwinian natural selection.  But factors like organismal dispersion or functional (embryonic) adequacy can account for at least some of this.  Longer-standing genes and genetic systems would be expected to be more entrenched because they can acquire fewer differences before they won't work with other elements in the organism.  This is at least compatible with the view we've expressed, and there could be some ways of testing the explanation.

This view means we need not worry about whether a variant is 'truly' neutral in the face of environmental screening.  We could even agree that there's no testable sense in which a variant evolves by 'pure' chance. Even very tiny differences in real function can evolve in a way that is statistically 'neutral'.  Again, this can be the case even if the trait to which such variants contribute is subject to clear natural or other forms of selection.

This view is also wholly compatible with the findings of GWAS, the evidence that every trait is affected by genetic variation to some extent, the fact that organisms are adapted to their environment in many ways and the fact that prediction based on genotyping is often a problematic false promise.  And because this is a spectrum, randomly generated by mutation, some variants and or traits they affect will be very harmful or helpful--and will look like strong, force-like natural selection.  These variants and traits led to Mendel, and led to the default if often tacit assumption that natural selection is the force that explains everything in life.

Further, it is important for all the same sorts of reasons that the shape of the spectrum--the relative amount of a given level of complexity--is not based on any distribution we know of and hence is not predictable, generally because it is the result of a long history of random and local context and contingencies, of various unknown strength and frequency (about the past, we can estimate a distribution but that doesn't mean we understand any real underlying probabilistic process that caused what we see).  This is interesting, because many aspects of genetic variation (and of the tree of life) can be fitted to a reasonable extent to various probability distributions (see Gene Koonin's paper or his book The Logic of Chance).  But these really aren't causal parametric 'laws' in the usual sense, but descriptions after the fact without rigorous causal characteristics.  Generally, prediction of the future will be weak and problematic.

In the view of life we've presented, evolution will have characteristics that are weak or unpredictable directional tendencies, and the same for genetic specificities (and hence predictive power). It is the trait that is in a sense predictable, not the effects of individual genes.

We think this view of evolution is compatible with the observed facts but not with many of the simplified ideas that are driving life sciences at present.

Our viewpoint is that the swarm of factors environmental and genomic means that chance is a major component even of functional adaptations, in the biodesic paths of life.

Tuesday, May 10, 2016

Darwin the Newtonian. Part IV. What is 'natural selection'?

If, as I suggested yesterday, genetic drift is a rather unprovable or even metaphysical notion, then what is the epistemological standing of its opposite: not-drift?  That concept implies that the reproductive success of the alternative genotypes under consideration is not equal. But since we saw yesterday that showing that two things are exactly equal is something of a non-starter, how different is its negation?  

Before considering this, we might note that to most biologists, those who think and those who just invoke explanations, non-drift means natural selection.  That is what textbooks teach, even in biology departments (and in schools 
of medicine and public health, where simple-Simon is alive and well). But natural selection implies systematic, consistent favoring of one variant over others, and for the same reason.  That is by far the main rationale for the routine if unstated assumption that today's functions or adaptations are due to past selection for those same functions: we observe today and retroactively extrapolate to the past.  It's understandable that we do that, and it was a major indirect way (along with artificial selection) in which Darwin was able to reconstruct an evolutionary theory that didn't require divine ad hoc creation events.   But there are problems with this sort of thinking--and some of them have long been known, even if essentially stifled by what amounts to a selectionist ideology, that is, a rather unquestioning belief in a kind of single-cause worldview.

What does exactly not-zero mean?
I suggested yesterday that drift, meaning exactly no systematic difference between states (like genotypes) was so illusive as to be essentially philosophical.  But zero-difference is a very specific value and may thus be especially hard to prove.  But non-zero is essentially an open-ended concept and might thus be trivially easy to show.  But it's not!

One alternative to two things being not zero is simply that they have some difference.  But need that difference be specifiable or of a fixed amount?  Need it be constant or similar over instances of time and place?  If not, we are again in rather spooky territory, because not being identical is not much if any help in understanding.  One wants to know by how much, and why--and if it's consistent or a fluke of sample or local circumstance.  But this is not a fixed set of things to check.

Instead of just 'they're different', what is usually implicitly implied is that the genotypes being compared have some particular, specific fitness difference amount, not just that they differ. That is what asserting different functional effects of the variants largely implies, because otherwise one is left asserting that they are different....sort of, sometimes, and this isn't very satisfying or useful.  It would be normal, and sensible, to argue that the difference need not be precisely, deterministically constant, because there's always a luck component, and ecological conditions change.  But if the difference varies widely among circumstances, it is far more difficult to make persuasive 'why' explanations. For example, small differences favoring variant A over variant B in one sample or setting might actually favor B over A in other times or places.  Then selection is a kind of willy-nilly affair--which probably is true!--but much more difficult to infer in a neat way, because it really is not different from being zero on average (though 'on average' is also easier to say than to account for causally).  If a difference is 'not zero', there are an infinity of ways that might be so, especially if it is acknowledged to be variable, as every sensible evolutionary biologist would probably agree is the case.

But then looking for causes becomes very difficult because among all the variants in a population, and all the variation in individual organisms' experience means that there may be an open-ended  number of explanations one would have to test to account for an observed small fitness difference between A and B.  And that leads to serious issues about statistical 'significance' and inference criteria.  That's because most alleged fitness differences are essentially local and comparative.  In turn that means the variant is not inherently selected but is context-dependent: fitness doesn't have a universal value, like, say, G, the universal Newtonian gravitational constant in physics, and to me that means that even an implicitly Newtonian view of natural selection is mistaken as a generality about life. 

If selection were really force-like in that sense, rather than an ephemeral, context-specific statistical estimate, its amount (favoring A over B) should approach the force's parameter, analogous to G, asymptotically: the bigger the sample and greater the number of samples analyzed the closer the estimated value would get to the true value.  Clearly that is not the way life is, even in most well-controlled experimental settings.  Indeed, even Darwin's idea of a constant struggle for existence is incompatible with that idea.

There are clearly many instances in which selective explanations of the classical sort seem specifically or even generally credible.  Infectious disease and the evolution of resistance is an obvious example.  Parallel evolution, such as independent evolution of, say, flight or similar dog-like animals in Australia and Africa, may be taken to prove the general theory of adaptation to environments.  But what about all the not dogs in these places?  We are largely in ad hoc explanatory territory, and the best of evolutionary theory clearly recognizes that.

So, in what sense does natural selection actually exist?  Or neutrality?  If they are purely comparative, local, ad hoc phenomena largely demonstrable only by subjective statistical criteria, we have trouble asserting causation beyond constructing Just-So stories.  Even with a plausible mechanism, this will often be the case, because plausibility is not the same as necessity.  Just-So stories can, of course, be true....but usually hard to prove in any serious sense.

Additionally, in regard to adaptive traits within or between populations or species, if genetic causation is due to contributions of many genes, as typically seems to be the case, there is phenogenetic drift, so that even with natural selection working force-like on a trait, there may be little if any selection on specific variants in that mix: even if the trait is under selection, a given allelic variant may not be.

Some other slippery issues
Natural selection is somewhat strange.  It is conceptually a passive screen of variation, but often treated as if an inherent property of a genotype (or an allele), whose value is determined on what else is in the same locus in the population.  Yet it's also treated as if this is inherent and unchanging property of the genotype...until any competing genotypes disappear.  As the favored allele becomes more common, its amount of advantage will increasingly vary because, due to recombination and mutation, the many individuals carrying the variant will also vary in the rest of their genomes, which will introduce differences in fitness among them (likewise, early on most carriers of the favored 'A' variant will be heterozygotes, but later on more and more will be homozygotes).  When the A variant becomes very common in the population, its advantage will hardly be detectable since almost all its peers fellws will have the same genotype at that site.  Continued adaptation will have to shift to other genes, where there still is a difference.  Some AA carriers will have detrimental variants at another gene, say B, and hence reduced fitness. Relatively speaking, some A's, or eventually maybe all A's, will have become harmful, because even in classical Darwinian terms selection is only relative and local.  So, selection even in the force-like sense, is very non-Newtonian, because it is so thoroughly context-dependent.  

Another issue is somatic mutation.  The genotypes that survive to be transmitted to the next generation are in the germ line.  But every cell division induces some mutations, and depending on when and where during development or later life a mutation occurs, it could affect the traits of the individual.  Even if selection were a deterministic force, it screens on individuals and hence that includes any effects of somatic mutation in those individuals.  But somatic mutations aren't inherited, so even if the mechanism is genetic their effects will appear as drift in evolutionary terms.  

Most models of adaptive selection are trait-specific.  But species do not evolve one trait at a time, except perhaps occasionally when a really major stressor sweeps through (like an epidemic).  Generally, a population is always subject to a huge diversity of threats and opportunities, contexts and changes.  Every one of our biological systems is always being tested, of in many ways at once. Traits are also often correlated with one another, so pushing on one may be pulling on another.  That means that even if each trait were being screened for separate reasons, the net effect on any one of the must typically be very very small, even if it is Newtonian in its force-like nature.  

The result is something like a Japanese pachinko machine.  Pachinko is popular type of gambling in Japan. A flurry of small metal balls bounces down from the top more or less randomly through a jungle of pins and little wheels, before finally arriving at the bottom.  The balls bounce off each other on the way in basically random collisions. The payoff (we could say it's analogous to fitness) is based on the balls that, after all this apparent chaos, end up in a particular pocket at the bottom.  In biological analogy, each ball can represent a different trait or perhaps individuals in a population. They bounce around rather randomly, constrained only by the walls and objects there--nothing steers them specifically. What's in the pocket is the evolutionary result. 

Pachinko machine (from Google images)
 (you can easily find YouTube videos showing pachinkos in action)

All similes limp, and these collisions are probably in truth deterministic, even if far too too complex to predict the outcome.  Nonetheless, this sort of dynamics among individuals with their differing genes of varying and context-specific effects, in diverse and complex environments, suggests why in this dynamic complex, change related to a given trait will be a lot like drift; there are so many that if each were too strongly force-like extinction would be more likely the result.  Further, since most traits are affected by many parts of the genome, the intensity of selection on any one of them must be reduced to be close to the expectations of drift. Adaptive complexity is another reason to think that adaptive change must be glacially slow, as Darwin stressed many times, but also that selection is much less force-like, as a rule.  After the fact, seeing what managed to survive, it looks compatible with force-like, straight-line selection.

Here, the process seems to rest heavily on chance.  But as we discussed in a post in 2014 in a series on the modes and nature of natural selection, we likened the course that species take through time to the geodesic paths that objects take through spacetime, that is determined (and there it really does seem to be 'determined') by the splattered matter and energy in any point it passes through.

An overall view
This leaves us in something of a quandary.  We can easily construct criteria for making some inferences, in the stronger cases, and testing them in some experimental settings.  We can proffer imaginative scenarios to account for the presence of organized traits and adaptations.  But evolutionary explanations are often largely or wholly speculative.  This applies comparably to natural selection and to genetic drift as well, and these are not new discoveries although they seem to be in few peoples' interest to acknowledge them fully.

Darwin wanted to show by plausibility argument that life on earth was the result of natural processes, not ad hoc divine creation events.  He had scant concepts of chance or genetic drift, because his ideas of the mechanism of inheritance were totally wrong.  Concepts of probabilism and statistical testing and the like were still rather new and only in restricted use.  Darwin would have no trouble acknowledging a role for drift.  How he would respond to the elusiveness of these factors, and that they really are not 'forces', is hard to say--but he probably would vigorously try to defend systematic selection by arguing that what is must have gotten here by selection as a force. 

The causal explanation of life's diversity still falls far short of the kind of mathematical or deterministic rigor of the core physical sciences, and even of more historical physical sciences like geology, oceanography, and meteorology.  Until someone finds better ways (if they indeed are there to be found), much of evolutionary biology verges on metaphysical philosophy for reasons we've tried to argue in this series.  We should be honest about that fact, and clearly acknowledge it.

One can say that small values are at least real values, or that you can ignore small values, as in genetic drift.  Likewise one can say that small selective effects will vary from sample to sample because of chance and so on.  But such acknowledgments undermine the kinds of smooth inferences we naturally hunger for.  The assumption that what we see today is what was the case in the past is usually little more than an assumption. This is a main issue we should confront in trying to understand evolution--and it applies as well to the promises being made of 'precision' prediction of genomic causation in health and medicine.  The moving tide of innumerable genotypic ways to get similar traits, at any time, within or between populations, and over evolutionary time, needs to be taken seriously. 

It may be sufficient and correct to say, almost tautologically, that today's function evolved somehow, and we can certainly infer that it got here by some mix of evolutionary factors.  Our ancestors and their traits clearly were evolutionarily viable or we wouldn't be here.  So even if we can't really trace the history in specifics, we can usually be happy to say that, clearly, whales evolved to be able to live in the ocean.  Nobody can question that.  But the points I've tried to make in this series are serious ones worth thinking seriously about, if we really want to understand evolution, and the genetic causal mechanisms that it has produced.