genetics
razib | April 28, 2009Dan MacArthur has a post, Genetics of complex traits in Europeans and East Asians: similarities and differences:
With those goals in mind, you can expect to see many more GWAS of non-European populations over the next couple of years, and some explicit comparisons of the differing genetic architecture of complex traits between populations. Exciting times for those of us interested in the genetic and evolutionary basis of between-population differences...
This reminds me of A variant of the gene encoding leukotriene A4 hydrolase confers ethnicity-specific risk of myocardial infarction:…
edyong | April 28, 2009The autism spectrum disorders (ASDs), including autism and its milder cousin Asperger syndrome, affect about 1 in 150 American children. There's a lot of evidence that these conditions have a strong genetic basis. For example, identical twins who share the same DNA are much more likely to both develop similar autistic disorders than non-identical twins, who only share half their DNA.
But the hunt for mutations that predispose people to autism has been long and fraught. By looking at families with a history of ASDs, geneticists have catalogued hundreds of genetic variants that are linked to…
amillikan | April 27, 2009
Related ScienceBlogs Posts:
Jake on genetics and obesity
Razib on obesity and heritability
purepedantry | April 27, 2009Razib and I have a discussion up at Bloggingheads.tv about genetics and behavior as well as a brief discussion of neuroeconomics. Check it out below the fold:
razib | April 27, 2009On the order of ~1 million years ago humans seem to have evolved dark skin. While light skin evolved several times, it looks like dark skin exhibits an "consensus sequence," so that all dark skinned peoples seem to have the same genetic architecture.
This chart (from Signatures of Positive Selection in Genes Associated with Human Skin Pigmentation as Revealed from Analyses of Single Nucleotide Polymorphisms) shows that when it comes to skin color related genes the populations of Bougainville Island (off the eastern coast of Papua New Guinea) and Sub-Saharan Africa are far closer than you…
razib | April 26, 2009Thankfully. Familial Resemblance of Borderline Personality Disorder Features: Genetic or Cultural Transmission?:
Borderline personality disorder is a severe personality disorder for which genetic research has been limited to family studies and classical twin studies. These studies indicate that genetic effects explain 35 to 45% of the variance in borderline personality disorder and borderline personality features. However, effects of non-additive (dominance) genetic factors, non-random mating and cultural transmission have generally not been explored. In the present study an extended twin-…
clock | April 25, 2009If you think that political or religious debates can get nasty, you haven't seen anything until you go online as see how much hate exists between people who love cilantro and those who hate cilantro. What horrible words they use to describe each other!!!!
Last weekend, I asked why is this and searched Twitter and FriendFeed for discussions, as well
Wikipedia and Google Scholar for information about it.
First - cilantro is the US name for the plant that is called coriander in the rest of the world. In the USA, only the seed is called coriander, and the rest of the plant is cilantro.
Second -…
razib | April 24, 2009What If Vitamin D Deficiency Is a Cause of Autism?:
As evidence of widespread vitamin D deficiency grows, some scientists are wondering whether the sunshine vitamin--once only considered important in bone health--may actually play a role in one of neurology's most vexing conditions: autism.
The idea, although not yet tested or widely held, comes out of preliminary studies in Sweden and Minnesota. Last summer, Swedish researchers published a study in Developmental Medicine and Child Neurology that found the prevalence of autism and related disorders was three to four times higher among Somali…
razib | April 23, 2009There are some papers out on the genome of the domestic cow out right now. ScienceNews has an overview:
Two competing research teams have cataloged the "essence of bovinity" found in the DNA of cattle, but not without disagreement on some essential points.
Reporting online April 23 in Science and April 24 in Genome Biology, the two groups compiled drafts of the bovine genome, identifying genes important for fighting disease, digesting food and producing milk.
I don't see the Genome Biology paper on the site yet, but there are two in Science. First, The Genome Sequence of Taurine Cattle: A…
razib | April 22, 2009Dan MacArthur's post, Can't find your disease gene? Just sequence them all..., is worth a read. He concludes:
But sequencing won't be enough: we need much better methods for sifting out the truly function-altering genetic variants from the biological noise. This is already difficult enough for protein-coding regions (as this study demonstrates); we currently have virtually no way of picking out disease-causing variants in the remaining 98% of the genome. There's a clear need for developing highly accurate and comprehensive maps of the functional importance of each and every base in the human…
razib | April 22, 2009One of the funnier aspects of the discovery of genes correlated with physical traits is that finding the genetic variant which explains 75% of the variation in blue eyes is interesting, but it isn't as if you now have a better way to find blue eyed people (though it is important for forensic work). But now there is apparently working on looking at pigmentation genes and how they effect melanoma risk in a manner which isn't visible to the eye: Dark Hair? Don't Burn? Your Genes May Still Put You At Risk For Melanoma:
Overall, the presence of certain MC1R variants was associated with a more…
edyong | April 21, 2009Nocturnal animals face an obvious challenge: collecting enough light to see clearly in the dark. We know about many of their tricks. They have bigger eyes and wider pupils. They have a reflective layer behind their retina called the tapetum, which reflects any light that passes through back onto it. Their retinas are loaded with rod cells, which are more light-sensitive than the cone cells that allow for colour vision.
But they also have another, far less obvious adaptation - their rod cells pack their DNA in a special way that turns the nucleus of each cell into a light-collecting lens.…
razib | April 20, 2009In response to the NEJM issue on personal genomics and the CDCV hypothesis, p-ter offers a proposal:
Let's follow Goldstein's back-of-the-envelope calculations: assume there are ~100K polymorphisms (assuming Goldstein isn't making the mistake I attribute to him, this includes polymorphisms both common and rare) that contribute to human height, that we've found the ones that account for the largest fractions of the variance, and that these fractions of variance follow an exponential distribution.
Now, assume you have assembled a cohort of 5000 individuals and done a genome-wide association…
razib | April 20, 2009Bryan Caplan notes & argues:
If you take a closer look at BG research, though, you'll notice something interesting. Virtually every BG study partitions variance into three sources: genes, shared family environment, and non-shared environment. Typical estimates are something like 40-50% for genes, 0-10% for shared family environment, and 50% for non-shared environment.
And what exactly is non-shared environment? Everything other than genes and family environment!
...
Nevertheless, I strongly suspect that if non-shared environment's contribution to behavioral variance were a lot smaller…
razib | April 19, 2009I long ago noticed that David Sloan Wilson was a contributor to The Huffington Post. My own inclination at this point is still to believe that Wilson pushes too hard for group selection, and on occasion engages in the same sort of rhetorical excess which he accuses his critics, such as Richard Dawkins, of. That being said it is probably a net positive that a scientist manages to get some face time in the mainstream-web media. In any case, he has a series of posts on group selection up.
Truth and Reconciliation for Group Selection I: Why it is Needed
Truth and Reconciliation for Group…
razib | April 18, 2009John Hawks has pointed out that the great archaeologist Colin Renfrew has been making the case that our species has been in genomic stasis for 50,000 years. He contends:
The genetic composition of living humans at birth (the human genotype) is closely similar from individual to individual today. That was an underlying assumption of the Human Genome Project and it is being further researched in studies of human genetic diversity. We are all truly born much the same. Moreover a child born today, in the twenty-first century of the Common Era, would be very little different in its DNA -- i.e., in…
razib | April 17, 2009In light of the relatively recent interaction of Bantu farmers and Pygmies in Central Africa, this paper is of note, Genetic and demographic implications of the Bantu expansion: insights from human paternal lineages:
The expansion of Bantu languages, which started around 5,000 years before present (YBP) in west/central Africa and spread all throughout sub-Saharan Africa, may represent one of the major and most rapid demographic movements in the history of the human species. Although the genetic footprints of this expansion have been unmasked through the analyses of the maternally-inherited…
razib | April 17, 2009A much more thorough post by Dan MacArthur on the recent issue of the New England Journal of Medicine & genomics.
amillikan | April 16, 2009While historical accounts of the Spanish Hapsburgs dynasty have suggested that prevalent inbreeding likely contributed to the family's downfall, such suspicions weren't supported by genetic data--until now. In a new paper in PLoS One, researchers traced the genes of the Hapsburgs through more than 3,000 individuals over 16 generations to calculate the "inbreeding coefficient," a value that is highly correlated with genetic defects. The study found that much of the family's infertility could be explained by genetic defects propagated by first-cousin inbreeding.
Related ScienceBlogs Posts:…
razib | April 16, 2009Another response by Etienne Patin, lead author of Inferring the Demographic History of African Farmers and Pygmy Hunter-Gatherers Using a Multilocus Resequencing Data Set, to a follow up post:
As to your hypothesis represented by the cladogram, this is a quite reasonable and interesting idea. Actually, the only method that we could use to prove it is to find human remains of Pygmies dating back to Bantu expansions, in regions that were colonized by Bantus. Population genetics cannot infer the presence of extinct populations. However, as stated in our article, Western and Eastern Pygmies may…