Quest for 'Genius Babies'?
50 minutes ago
|Sad mermaid. (source)|
|Or this just did. (source)|
|Cadieu et al., 2009|
The vast mosaic of dog shapes, colors, and sizes is decided largely by changes in a mere handful of gene regions. The difference between the dachshund's diminutive body and the Rottweiler's massive one hangs on the sequence of a single gene. The disparity between the dachshund's stumpy legs—known officially as disproportionate dwarfism, or chondrodysplasia—and a greyhound's sleek ones is determined by another one. The same holds true across every breed and almost every physical trait. In a project called CanMap, a collaboration among Cornell University, UCLA, and the National Institutes of Health, researchers gathered DNA from more than 900 dogs representing 80 breeds, as well as from wild canids such as gray wolves and coyotes. They found that body size, hair length, fur type, nose shape, ear positioning, coat color, and the other traits that together define a breed's appearance are controlled by somewhere in the neighborhood of 50 genetic switches. The difference between floppy and erect ears is determined by a single gene region in canine chromosome 10, or CFA10. The wrinkled skin of a Chinese shar-pei traces to another region, called HAS2. The patch of ridged fur on Rhodesian ridgebacks? That's from a change in CFA18. Flip a few switches, and your dachshund becomes a Doberman, at least in appearance. Flip again, and your Doberman is a Dalmatian. "The story that is emerging," says Robert Wayne, a biologist at UCLA, "is that the diversity in domestic dogs derives from a small genetic tool kit."
|Kevin and me and our Westie, Elroy, and our French Bulldog, Murphy.|
|Elroy (I fit in your phone!)|
Testing your dog with Wisdom Panel® 2.0 begins when you use the cheek swabs to simply collect a small DNA sample from inside your dog’s cheek and send the swabs into the laboratory. Once your sample is received at our lab it is scanned into our database and assigned to a batch for testing. It then undergoes processing to extract the DNA from your dog’s cells which is examined for the 321 markers that are used in the test. The results for these markers are sent to a computer that evaluated them using a program designed to consider all of the pedigree trees that are possible in the last three generations. The trees considered include a simple pedigree with a single breed (a likely pure-bred dog), two different breeds at the parental level (a first-generation cross), all the way up to a complex tree with eight different great-grandparent breeds allowed. Our computer used information from our extensive breed database to fill these potential pedigrees. For each of the millions of combinations of ancestry trees built and considered, the computer gave each a score representing how well that selected combination of breeds matched to your dog’s data. The pedigree with the overall best score is the one which is selected and provided to you in your dog’s individualized report.This doesn't really cut it for me. I want to know what the methods are and this is all they provide in answers to "Science Based Questions!" This isn't helping much:
Not only does the computer analyze a dog’s DNA for the breeds and their likely proportions in the dog’s ancestry, but it also models which side of a dog’s ancestry each breed is likely coming from.
Wisdom Panel only uses what are called autosomal DNA markers, chromosomes that contain most of the genetic instructions for every canine’s body make up (height, weight, size etc.). There are no markers from either the so-called sex chromosomes (the canine X or Y chromosomes). Mitochondrial DNA, or Y-chromosome DNA testing, is rather different as these parts of the genome are passed on intact from mother to child and father to son respectively, but are therefore only representative of either the female or the male lineage. Autosomal DNA is inherited both from the maternal and paternal lineages equally and constantly shuffled by a process called recombination at each successive generation, and therefore is able to give useful information on the breeds found on both sides of a dog’s lineage.
To find the genetic markers that performed best at distinguishing between breeds, Mars Veterinary™ tested over 4,600 SNPs (single nucleotide polymorphisms or genetic markers, where genetic variation has been found between different dogs), from positions across the whole canine autosomal genome from over 3,200 dogs. To further refine the search, Mars Veterinary determined the best 1,536 genetic variations and ran them against an additional 4,400 dogs from a wide range of breeds. This stage of testing resulted in the selection of the final panel of DNA markers that performed best at distinguishing between breeds, ultimately creating the Wisdom Panel genetic database which presently covers over 200 different breeds.
Wisdom Panel® 2.0 breaks down a dog’s lineage in the form of an ancestry tree. This allows you to see which breeds are present at a parent, grandparent, or great-grandparent level. Keep in mind that a parent contributes 50% of their DNA to the puppy while a grandparent contributes about 25% of their DNA on average to the puppy. It follows that a great-grandparent would contribute approximately 12.5% of their DNA to the puppy on average.
Since each of these different levels can contribute different amount of DNA to the puppy, you can see a variety of influence in the puppy’s physical and behavioral traits. With a parental breed, you are likely to see some physical and behavioral traits from this breed represented unless some of the genes are recessive (requires two copies of the gene variant to show it). Examples of recessive traits include longhair in most breeds, a clear yellow or red hair coat, a brown or chocolate hair coat, and prick or upright ear set (e.g. like a German Shepherd Dog). You may see traits from breeds at the grandparent level and it becomes less likely to see physical and behavioral traits from breeds at the great-grandparent level unless those traits are dominant (requires only one copy of the gene variant to show it). Examples of dominant traits include shorthair in most breeds, black hair coat, black nose, a drop or down ear set (e.g. like a Beagle), and merle/dapple (e.g. like a Australian Shepherd or Great Dane).
|Before her greybeard took over.|
...clinically meaningful improvements on global and specific neurobehavioral outcomes were observed in the general study population. The improvements were statistically significant in pediatric patients with more severe impairments in sociability -- a core symptom of fragile X syndrome.
“In our Phase 2 study, we were very excited to observe clinically meaningful improvements in social impairment in patients receiving STX209—marking the first time a drug candidate has positively impacted a core symptom of fragile X syndrome. The Phase 3 study is the most comprehensive study ever undertaken in patients with fragile X syndrome and represents the first time that a drug candidate will be evaluated for a core symptom of fragile X syndrome as the primary endpoint.”But, production is now being halted because the drug has not proven to be a successful enough treatment for social withdrawal in children with autism in the Phase 3 study. This seems to be a bureaucratic and financial issue rather than a scientific one. According to a Seaside vice president, quoted on the "Age of Autism" website,
The FDA requires companies to pick one, and only one, assessment as the “primary endpoint” of the study. In their eyes, the result on that one pre-selected endpoint makes or breaks the study. In our recent autism study, STX209 did not show an advantage over placebo (see above) on the primary endpoint of social withdrawal, so the FDA and some news reporters regard it as a negative study. In fact, STX209 did show advantages over placebo on a number of other assessments. Some of these secondary endpoints are just as meaningful as the social withdrawal assessment, or even more so, but in the FDA’s eyes, they don’t make the study a positive study, because they were not pre-selected as the “primary endpoint.”The pharmaceutical giant, Roche, had been backing development of the drug, but they've recently pulled their support as they cut back on research and development in general, and it seems that Seaside cannot afford to continue manufacturing the drug alone.
"The study termination is due to resource limitations at seaside, and is not due to any safety issue associated with STX209. We know that this termination will be disruptive and disappointing for many. We are planning to complete phase 3 and the results of this study should be available late summer. If the results are positive, seaside will discuss with FDA the required next steps for approval of STX209.
"This means the drug could potentially become available in the future but there is still nothing guaranteed."Parents who saw tremendous improvement in their children on this medication are devastated.