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Search Results for 'slc24a5'
To classify humanity is not that hard
In my post below I quoted my interview L. L. Cavalli-Sforza because I think it gets to the heart of some confusions which have emerged since the finding that most variation on any given locus is found within populations, rather than between them. The standard figure is that 85% of genetic variance is within continental [...]
Every variant with an author!
I recall projections in the early 2000s that 25% of the American population would be employed as systems administrators circa 2020 if rates of employment growth at that time were extrapolated. Obviously the projections weren’t taken too seriously, and the pieces were generally making fun of the idea that IT would reduce labor inputs and [...]
Not all genes are equal in the eyes of man
A few days ago I was listening to an interview with a reporter who was kidnapped in the tribal areas of Pakistan (he eventually escaped). Because he was a Westerner he mentioned offhand that to “pass” as a native for his own safety he had his guides claim he was Nuristani when inquiries were made. [...]
Chosen genes of the Chosen People
Last spring two very thorough papers came out which surveyed the genetic landscape of the Jewish people (my posts, Genetics & the Jews it’s still complicated, Genetics & the Jews). The novelty of the results was due to the fact that the research groups actually looked across the very diverse populations of the Diaspora, from [...]
Desmond Tutu, Spaniards, and genetic distance
Since we’ve been talking about Fst a fair amount, I thought it might be nice to put it in some concrete graphical perspective. First, to review Fst in the genetic context measures the proportion of genetic variation which can be attributed to between population differences. To give a “toy” example if you randomly divided the [...]
PCA, Razib around the world (a little)
I have put up a few posts warning readers to be careful of confusing PCA plots with real genetic variation. PCA plots are just ways to capture variation in large data sets and extract out the independent dimensions. Its great at detecting population substructure because the largest components of variation often track between population differences, [...]
Better prediction through better measurement
One of the most successful achievements of the “post-genomic era” has been the elucidation of the genetic architecture which undergird the variation in human pigmentation. I like to point out that in 2005 the geneticist Armand Leroi observed in his book Mutants that we didn’t know the genetics of normal variation in relation to the [...]
Natural selection & recombination in the human genome
If you are like me, and if you are reading this weblog there is a significant probability you are like me, you read L. L. Cavalli-Sforza‘s History and Geography of Human Genes in the 1990s, and in the early aughts Spencer Wells’ A Journey of Man. Science has come very far in the last in [...]
OCA2 makes East Asians white and Europeans blue
Over the history of this weblog I have blogged about pigmentation a fair amount. The major reason is that that’s where the money is; unlike height, let alone intelligence, the genetic architecture and evolutionary history of pigmentation has been elucidated with relative clarity. That is, we know roughly the number and nature of the genes [...]
The parallel lives of threespine stickleback
A few days ago I pointed to a paper which suggests the possible utility of looking at selection on standing genetic variation on quantitative traits to get a sense of the role of adaptation in the human genome. We humans like to think we’re a complex species, so I see no a priori reason why [...]
The genetics of Scottish hair color variation
In the aughts the elucidation of human pigmentation genetics was of one the major successes of ‘omic’ techniques. The fact that humans exhibit some continuous variation in complexion was strongly suggestive that more than one gene was at work to generate the range of the phenotype. On the other hand pedigree based studies going back [...]
Obesity as part of normal human variation
Common body mass index-associated variants confer risk of extreme obesity: To investigate the genetic architecture of severe obesity, we performed a genome-wide association study of 775 cases and 3197 unascertained controls at 550 000 markers across the autosomal genome. We found convincing association to the previously described locus including the FTO gene. We also found [...]
93 ancestrally informative markers to categorize them all
An ancestry informative marker set for determining continental origin: validation and extension using human genome diversity panels: Results In this study, genotypes from Human Genome Diversity Panel populations were used to further evaluate a 93 SNP AIM panel, a subset of the 128 AIMS set, for distinguishing continental origins. Using both model-based and relatively model-independent [...]
What makes the mice nice
Domestication has a long history. It predates the invention of writing by thousands of years. In the history of biology the study of domestication is closely connected to the emergence of experimental and theoretical biology out of the shadow of natural history. Chapter I of The Origin of Species is preoccupied with animal breeding. The [...]
Adaptation might not be a spherical cow
In Natural selection of a human gene: FUT2 I referred to a paper, Signals of recent positive selection in a worldwide sample of human populations (see my earlier review). Now the same group has a follow up paper which takes a slightly different tack, The Role of Geography in Human Adaptation: Since the beginning of [...]
Skin color is not race
One of the peculiarities of American discussion about race is that skin color is assumed to be synonymous with racial distinctions. That is, skin color is not just a trait, but it is the trait which defines between population differences. There’s a reason for this, the skin is the largest organ and it is very [...]
Genetics of human pigmentation
Richard Sturm in Human Molecular Genetics has a really good review of the current state of pigmentation genetics, with a human centric focus: The genetic basis underlying normal variation in the pigmentary traits of skin, hair and eye colour has been the subject of intense research directed at understanding the diversity seen both between and [...]
A transracial identity
Recently I’ve been having an on-and-off discussion with a friend about the bioethical implications of neo-eugenics. I brought up one particular issue as a thought experiment: how about selective abortion of dark-skinned fetuses among South Asians? The light and dark variants of SLC24A5 segregate within the South Asian population at high frequencies, the light variant [...]
Interracial sex or Mendelian segregation?
Over at The Root Keith Adkins has a post, Sandra Laing: Born Black with White Parents: I’m no geneticist or biologist, but it looks like Sandra is a product of an black South African and maybe a white Afrikaneer. I’m saying, it looks like somebody in her family was lying. The tests they used to [...]
Ivory & teak, how related are South Asians & Europeans?
The post yesterday about the deletion which results in heart disease later in life had some interesting ancestry related material. This makes sense, the genetic maps which I post on now and then ultimately have a medical rationale behind them; eliminate population structure so that you don’t have spurious correlations confusing you when you try [...]
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