genetics
razib | November 1, 2007Here is another write up of Genetic determinants of hair, eye and skin pigmentation in Europeans. Generally echoes my own impressions, though I offer the link in the hope it is more readable! The paper was hard to reduce because of the contingency and polymorphism across the many genes affecting the many traits.
Update: Links fixed!
razib | October 29, 2007Until recently archeologists held to a model called Clovis First which posited that the Amerindians were descended from Siberian hunters who swept down from Beringia 13,000 years ago and spread rapidly north to south. Findings such as Monte Verde have thrown a cloud over the cleanliness of this hypothesis and there doesn't seem to be any claimant to the throne at this point.
Geneticists have been weighing in on this topic now and then. Roughly, one line of results seems to suggest that the Amerindians have been resident on the New World for far longer than 10,000 years. Another finding has…
razib | October 25, 2007Sometimes science is just too cool! A Melanocortin 1 Receptor Allele Suggests Varying Pigmentation Among Neanderthals:
The melanocortin 1 receptor (MC1R) regulates pigmentation in humans and other vertebrates. Variants of MC1R with reduced function are associated with pale skin color and red hair in humans primarily of European origin. We amplified and sequenced a fragment of the MC1R gene (mc1r) from two Neanderthal remains. Both specimens have a mutation not found in ~3700 modern humans. Functional analyses show that this variant reduces MC1R activity to a level that alters hair and/or…
razib | October 23, 2007Another day, and another genome-wide association study. Genetic determinants of hair, eye and skin pigmentation in Europeans:
...We carried out a genome-wide association scan for variants associated with hair and eye pigmentation, skin sensitivity to sun and freckling among 2,986 Icelanders. We then tested the most closely associated SNPs from six regions--four not previously implicated in the normal variation of human pigmentation--and replicated their association in a second sample of 2,718 Icelanders and a sample of 1,214 Dutch. The SNPs from all six regions met the criteria for genome-…
grrlscientist | October 22, 2007tags: Gene Genie, blog carnival
The 18th edition of Gene Genie is now available. This blog carnival links to essays about DNA technology. Interestingly, this carnival also includes a streaming video of the Personal Genomics (PG) Tips Chimp!
purepedantry | October 22, 2007James Watson, Nobel Laureate and member of the Watson-Crick duo that discovered DNA, has been suspended from Cold Spring Harbor Laboratory after some comments about race and genetics:
James Watson, in London to promote a new book, was forced to return to New York after Cold Spring Harbor Laboratory, Long Island, relieved him of his duties because of his apparent views. It follows a hellish week for the 79-year-old geneticist who helped to unravel the structure of DNA more than 50 years ago.
After being quoted in The Sunday Times saying that he was "inherently gloomy about the prospect of…
razib | October 20, 2007Carl Zimmer interviews Craig Venter (video). They're talking most genomics and creating life from "scratch." Also, Esther Dyson talks about the personal genome.
razib | October 15, 2007At my other site I've put up 10 questions for Jon Entine. He has a new book out, Abraham's Children: Race, Identity, and the DNA of the Chosen People, which covers the fascinating area of Jewish genetics.
sporte | October 14, 2007October is a month of darkness, mystery, and dread. Only one holiday brings joy in October and even then, October joy is distilled through fear and apprehension. In the early evenings the sun hurries home and once familiar objects loom ominously in the dark. Giant spiders appear out the fog, lurking on webs that span our walkways and doors. Even Mendel's Garden is dark and malevolent when October greys our skies.
genetics, Mendel's garden, blog carnival.
Horror stories for adults
October looks bleaker than usual if you're out of work and not getting paid. If your income matches this…
razib | October 11, 2007The New York Times has an interesting article, Picky Eaters? They Get It From You, which I'm sure many parents can relate to. Here's the most critical part:
The study, led by Dr. Lucy Cooke of the department of epidemiology and public health at University College London, was published in the American Journal of Clinical Nutrition in August. Dr. Cooke and others in the field believe it is the first to use a standard scale to investigate the contribution of genetics and environment to childhood neophobia.
According to the report, 78 percent is genetic and the other 22 percent environmental.
"…
clock | October 9, 2007Another thing I will also have to miss - the Inaugural Event of the 2007-2008 Pizza Lunch Season of the Science Communicators of North Carolina (SCONC), on October 24th at Sigma Xi Center (the same place where we'll have the Science Blogging Conference). Organized by The American Scientist and the Burroughs Wellcome Fund, the first Pizza Lunch Session will feature Dr.Fred Gould, professor of Entomology and Genetics at NCSU (whose Insect Ecology class blows one's mind - one of the best courses I have ever taken in my life). Fred recently received The George Bugliarello Prize for an…
clock | October 9, 2007My former SciBling David Dobbs regularly posts on the SciAm Blog, usually bringing in guest contributors highlighting novel research in neuroscience. Today, he invited Charles Glatt to review an interesting study on the interaction between genes and environment in development of depression. David writes:
This week reviewer Charles Glatt reviews a study that takes this investigation a level deeper, examining how two different gene variants show their power -- or not -- depending on whether a child is abused, nurtured, or both. As Glatt describes, this study, despite its grim subject,…
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, 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…
pharyngula | October 8, 2007I've known for years that this was going to happen: Mario Capecchi, Oliver Smithies and Briton Martin Evans have won the Nobel Prize in Medicine for their work on targeted gene mutations. If you're interested in what kinds of work they've done, I described one paper on Hox regulatory evolution, and this work on the evolution of the Hox code wouldn't have been possible without their knockout techniques.
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, 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, 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…