L. L. Cavalli-Sforza’s The History and Geography of Human Genes is a book I reference a great deal. Cavalli-Sforza is the godfather of the field of historical population genetics, the phylogeography of humankind. Though his work was on classical autosomal markers, the huge literature which drew inferences from Y chromosomal and mtDNA variation followed in the wake of the The History and Geography of Human Genes. Spencer Wells, the director of the Genographic Project, alluded to Cavalli-Sforza’s influence in The Journey of Man. But at this point I think we have to be very careful of making inferences about the past from present patterns of genetic variation. This is made most stark by the fact that ancient DNA, which is a snapshot of the past, as opposed to an inference of it, sometimes diverges from our expectations based on present patterns of variation in surprising ways.
Month: August 2011
The "evo-devo" peak
Jerry Coyne has a post up which critiques an extremely breathless review of a new book, Epigenetics Revolution. Overall I agree with the thrust of Coyne’s take. Epigenetics is real, and probably important, but it doesn’t imply that there’s a revolution and that everything that has come before needs to be thrown out. But I was struck by one of Coyne’s asides:
…This study has segued into the new field of “evo devo,” which tries to understand the evolutionary basis of developmental genetics. “Evo devo” itself has, of course, led to its own important discoveries, like the presence and conservation of homeobox genes, the use of the same genes over and over again in forming similar but non-homologous traits (e.g., PAX6 in the formation of fly eyes and vertebrate eyes), and the linear arrangement of genes in some organisms (e.g., Drosophila) that correspond to the linear arrangement of body parts they affect.
Twin studies are not useless
A few friends have pinged me on this piece in Slate, Double Inanity: Twin studies are pretty much useless. The headline is bold, but the piece is just a sloppy mishmash. It’s really something amenable for a major “fisking,” but I generally don’t like doing that sort of thing, because it doesn’t seem a optimal allocation of time (though I have to note that the author seems to be implicitly using a colloquial form of the concept of heritability, which I think is going to confuse an already naive audience). A lot of the article is taken up with criticisms of political scientist John Alford’s behavior genetic findings on the heritability of ideology. I’ve had personal communication with other researchers in this area who actually are broadly critical of Alford’s methodology, but they’re still strongly invested in using genomics and behavior genetics to explore this issue. In other words, rejecting Alford’s conclusions does not entail that you just reject twin studies, as such.
Raising funds on Google+ vs. Facebook
As some of you know I’ve been looking for a Malagasy genotype. I found one. Or at least a potential one. At this point I need to have the person genotyped. I’ve sent the kit overseas, and within 1-2 months I should have a post up analyzing the ancestral affiliations of this individual (who is of Betsileo background). All that being said this costs money, and I’m willing to pay for it myself (in fact, I have). But the total costs is ~$280, and that’s not trivial. I’d like to do this sort of “crowd-sourced” analysis in the future, but not at this personal cost (I’m not including my labor hours, just the bare minimum fixed costs of shipping the materials, and typing the sample).
Eugenics as a luxury of the affluent
In the comments below Jason says in regards to the connection between eugenics and genocide and the “slippery slope”:
In your current comfortable first world circumstances, you are right the slope is perhaps not that slippery. I hope you are never tested in a less comfortable setting as then I think you might find it can be pretty slippery after all.
A reference to the interlocutor’s status as a citizen of the comfortable First World (which itself is a somewhat archaic term by now I think) seems de rigueur in many arguments. And I think many people will find it plausible that someone in an affluent consumer society would be blind to the “dark side” of eugenics, and how it could lead to genocide. But I think this plausibility is entirely superficial, and collapses upon closer inspection. Rather, it is I believe in “First World” and advanced nations where the likelihood of the ubiquity of eugenics and possible genocide predicated on systematic eugenics is going to be the most probable outcome.
The rap guide to evolution
The lyrics are, for the most part, witty, sophisticated and scientifically accurate; and they lack the earnest defensiveness that sometimes haunts lectures on evolution. I spotted one or two small slips — a confusion of the praying mantis with the Australian redback spider (oh no!) — and there are a few moments of poetic license that a po-faced pedant might object to. Otherwise, it’s pretty rigorous.
People don't accept evolution just because they're smart
If we look at each wordsum category separately, which ones are significantly different? I ask because the trend seems to reflect the liberal-conservative split (low and high lean left; middle leans conservative). It also seems to mirror educational attainment–moderately educated people (some/completed college) are more likely to be conservative.
Hard to suss out causal factors here.
Well, here’s a logistic regression from the GSS:
Don’t take it too seriously. A lot of these are categorical variables which happen to be rank ordered (e.g., most liberal = 1 and most conservative = 7). But as you can see the WORDSUM correlation disappears when you throw in other variables. In fact, even education isn’t statistically significant anymore. That seems ludicrous, but remember that Biblical literalism is strongly correlated with lower levels of education and intelligence. Once you throw that in there as an explanatory variable it sucks up all the oxygen.
Smart people accept evolution
At Culture of Science there’s a little discussion about whether acceptance of evolution indicates intelligence. Looking at the GSS data there doesn’t seem to be a strong causal relationship when you control for other variables. But there is a correlation. That correlation can be explained by the fact that, for example, people who are Biblical literalists tend to be duller than those who are not, and Biblical literalists don’t accept evolution (in fact, I’ve seen evidence that very intelligence Biblical literalists are more Creationist than their duller co-religionists, probably because they’re more coherent in their beliefs).
With that, I’ll leave you with a screenshot of the results for WORDSUM, a 10 word vocabulary test, against acceptance or rejection of human evolution from other organisms (note that the numbers below the proportions are weighted sample sizes):
Evolution is a signal for real Republican populism
New York Magazine has a rundown of the attitudes of some of the G.O.P. candidates for the nomination in regards to evolution. Remember, this is an issue which is split down the middle in the American populace, but elites have a strong skew toward accepting evolution. This is probably why despite a majority Creationist primary electorate in 2008 the majority of Republican candidates still agreed with the evolutionary position. In 2012 it looks like the Creationism or semi-Creationist contingent is going to get larger.
In the General Social Survey they asked in the late 2000s whether respondents accepted that “humans developed from animals.” The response was dichotomous. Here are some results for various population groups:
