razib | October 9, 2007The paper Genetic Evidence for the Convergent Evolution of Light Skin in Europeans and East Asians has some great maps which show the frequencies of major alleles for some major skin color genes. I've placed them below the fold with some minor edits (added the gene label prominently to each map).
razib | October 9, 2007Predicting Odor Pleasantness from Odorant Structure: Pleasantness as a Reflection of the Physical World:
Although it is agreed that physicochemical features of molecules determine their perceived odor, the rules governing this relationship remain unknown. A significant obstacle to such understanding is the high dimensionality of features describing both percepts and molecules. We applied a statistical method to reduce dimensionality in both odor percepts and physicochemical descriptors for a large set of molecules. We found that the primary axis of perception was odor pleasantness, and…
razib | October 9, 2007I have posted before on recent work which seems to establish that the OCA2 locus is responsible for the majority of the variation within populations where both blue and brown eyes are extant. Well, now there's a massive paper out by Tony Frudakis, Multilocus OCA2 genotypes specify human iris colors, that adds even more detail in terms of the markers (SNPs) which can predict eye color:
Human iris color is a quantitative, multifactorial phenotype that exhibits quasi-Mendelian inheritance....Herein, we describe an iris color score (C) for quantifying iris melanin content in-silico and undertake…
razib | October 8, 2007An Open Access review paper in Human Molecular Biology, Challenges in human genetic diversity: demographic history and adaptation, has a short and easy-to-digest review of many of the major findings over the past 5 years in human evolutionary genomics and the "big picture" implications:
Modern human genetic diversity is the result of demographic history, and selective effects that have acted to adapt different populations to their environments. Broad patterns of global diversity are well explained by geography, based on an out-of-Africa model of early human evolution. Genome-wide searches for…
razib | October 8, 2007Ancestral reconstruction of segmental duplications reveals punctuated cores of human genome evolution:
Human segmental duplications are hotspots for nonallelic homologous recombination leading to genomic disorders, copy-number polymorphisms and gene and transcript innovations. The complex structure and history of these regions have precluded a global evolutionary analysis. Combining a modified A-Bruijn graph algorithm with comparative genome sequence data, we identify the origin of 4,692 ancestral duplication loci and use these to cluster 437 complex duplication blocks into 24 distinct groups…
razib | October 8, 2007Genetic triple dissociation reveals multiple roles for dopamine in reinforcement learning:
...Here, we show with genetic analyses that three independent dopaminergic mechanisms contribute to reward and avoidance learning in humans. A polymorphism in the DARPP-32 gene, associated with striatal dopamine function, predicted relatively better probabilistic reward learning. Conversely, the C957T polymorphism of the DRD2 gene, associated with striatal D2 receptor function, predicted the degree to which participants learned to avoid choices that had been probabilistically associated with negative…
razib | October 8, 2007Shelley needs help to win a blogging scholarship. If you're so inclined vote for Shelley. General information on the scholarship.
razib | October 7, 2007Amusing story in The New York Times. As I have said, scientific genealogy can answer specific and narrow questions; though in this case I think there's going to be enough wiggle room for the myth-makers to contine publishing books (note: I don't know which ones are the mythical ones!).
razib | October 7, 2007The Seattle Times has a piece titled Anthropology: the great divide. Here's the essential bit:
At the extremes, one school of thought insinuates dark, possibly racist intentions of scientists under sway of their Eurocentric biases, linear thinking and arrogance in their dealings with modern tribes. The other school is dismissive of the slaves to political correctness and their warm and fuzzy research -- or, as one physical anthropologist smirked to another: "What do you think? Are cultural anthropologists scientists?"
...
On one side were cultural and social anthropologists, generally…
razib | October 7, 2007You'll never know what you might find if you go looking....
So, on my question for skin color genes, Signatures of Positive Selection in Genes Associated with Human Skin Pigmentation as Revealed from Analyses of Single Nucleotide Polymorphisms:
...We identified eight genes that are associated with the melanin pathway (SLC45A2, OCA2, TYRP1, DCT, KITLG, EGFR, DRD2 and PPARD) and presented significant differences in genetic variation between Europeans, Africans and Asians. In six of these genes we detected, by means of the EHH test, variability patterns that are compatible with the hypothesis of…
razib | October 5, 2007
Pew has released a massive survey of global attitudes. There's a lot of good stuff you can find if you dig deep into the massive 2 MB PDF that has all the results. Something I found interesting....
In response to the query "Do you have to believe in God to be moral?" Here are some select percentages for responses in the affirmative:
United States - 57
Canada - 30
Germany 39
Spain - 25
Italy - 24
Britain - 22
France - 17
Sweden - 10
Poland - 29
Turkey - 84
Lebanon - 66
Israel - 44
Bangladesh - 90
Pakistan - 88
Indian - 66
South Korean - 56
Japan - 33
China - 17
OK, so here are my thoughts…
razib | October 5, 2007Effects of metabolic rate on protein evolution:
Since the modern evolutionary synthesis was first proposed early in the twentieth century, attention has focused on assessing the relative contribution of mutation versus natural selection on protein evolution. Here we test a model that yields general quantitative predictions on rates of protein evolution by combining principles of individual energetics with Kimura's neutral theory. The model successfully predicts much of the heterogeneity in rates of protein evolution for diverse eukaryotes (i.e. fishes, amphibians, reptiles, birds, mammals)…
razib | October 5, 2007Over the past few weeks I've been looking closely at all the skin color related genes in humans which have been studied over the past few years. A little over two years ago the evolutionary biologist Armand Leroi wrote:
We don't know what the differences are between white skin and black skin, European skin versus African skin. What I mean is we don't know what the genetic basis of that is. This is actually amazing. I mean, here's a trait, trivial as it may be, about which wars have been fought, which is one of the great fault lines in society, around which people construct their identities…
razib | October 4, 2007Evolution happens faster than originally assumed:
Studying animals from Bighorn sheep to guppies, the research has revealed that animals are evolving to human changes in the environment within 200 generations. "They can be pretty dramatic [changes]," Kinnison said.
...
"People are just catching on to how important these changes are," Kinnison said. The changes discovered in these species showed that those driven by human intervention appear nearly twice as fast as those driven by a natural environment, according to a press release.
The above was a press release from the University of Maine…
razib | October 3, 2007Paired-End Mapping Reveals Extensive Structural Variation in the Human Genome:
Structural variation of the genome involves kilobase- to megabase-sized deletions, duplications, insertions, inversions, and complex combinations of rearrangements. We introduce high-throughput and massive paired-end mapping (PEM), a large-scale genome sequencing method to identify structural variants (SVs) ~3 kb or larger that combines the rescue and capture of paired-ends of 3 kb fragments, massive 454 Sequencing, and a computational approach to map DNA reads onto a reference genome. PEM was used to map SVs in an…