The effect of economic recession on population health:
Economic recessions have paradoxical effects on the mortality trends of populations in rich countries. Contrary to what might have been expected, economic downturns during the 20th century were associated with declines in mortality rates. In terms of business cycles, mortality is procyclical, meaning it goes up with economic expansions and down with contractions, and not countercyclical (the opposite), as expected. So while most nations enjoyed sustained declines in mortality during the last century, the pace of the decline has been slower during economic booms and greater during so-called busts. The first rigorous studies demonstrating this trend have appeared only in the past 9 years, although the concept is not new. In contrast, for poor countries, shared economic growth appears to improve health by providing the means to meet essential needs such as food, clean water and shelter, as well access to basic health care services. But after a country reaches $5000 to $10 000 gross national product (GNP) per capita (or gross domestic product or gross national income per capita, all of which are similar for our purposes here), few health benefits arise from further economic growth…Health trends in Sweden illustrate this effect.
Greg Cochran told me about this phenomenon in regards to the Great Depression last year.
Much of evolutionary biology focuses on ultimate causation–identifying the evolutionary forces that have led the world to be as it is today, without much regard for the nuts and bolts of how organisms work. Much of molecular biology, on the other hand, focuses on proximate causation–understanding how the world works without much regard to how it came to be that way.
It’s nice, then, to see the two joined in an elegant fashion; a recent paper on the evolution of pigmentation in deer mice does just that. About 8-10 thousand years ago, a novel habitat arose in the middle of Nebraska in the form of a large field of sand dunes. Since then, the a population of deer mice adapted to the habitat by evolving a lighter coat color (though I’m having issue with images on blogger, an example is in part A of this figure).
The authors show that this decrease in pigmentation is due to changes in the temporal expression of the agouti protein (this protein is part of the “canonical” pigment type-switching pathway)–light mice express agouti for longer than dark mice during hair development. They’re able to show that this change in expression pattern correlates perfectly with a deletion of a single amino acid in agouti, though they hesitate to claim that this is the true causal mutation (this polymorphism is perfectly correlated with others in the region).
The allele shows classical signatures of having experienced a selective sweep, and the authors estimate that the allele arose sometime after 10kya, after the formation of the dunes that produced the selective advantage. It’s difficult, of course, to prove that this polymorphism wasn’t segregating prior to the formation of the dunes, but if it was, it was certainly at very low frequency. In all, this is a very nice story, and a great example of the power of molecular approaches to the study of evolution, even in non-model organisms.
Citation: On the Origin and Spread of an Adaptive Allele in Deer Mice. Catherine R. Linnen, Evan P. Kingsley, Jeffrey D. Jensen, and Hopi E. Hoekstra (28 August 2009). Science 325 (5944), 1095. [DOI: 10.1126/science.1175826]
Mike the Mad Biologist points out that Massachusetts, New Jersey, Minnesota and New Hampshire do better on math scores for elementary age students than most of Europe, and are competitive with Asia. Here are Mike’s factors for why this might be:
-Low child poverty rates as measured by school lunch subsidies (a common proxy for poverty).
-Low divorce rates.
-Effective public health departments. MA, NJ, and MN have very good public health systems, and NH has some excellent programs (e.g., electronic syndromic surveillance)
-High incomes. Overall, these are healthy state economies (as good as one can get anyway).
-Educated adult populations.
I’ll add a sixth: they’re all close to Canada. I pointed out last year that being close to Canada also prevents murder. Being close to Canada also persuaded whites to vote for Barack Obama. It even seems to have a salubrious effect on life expectancy. I wonder if American xenophobia can explain the long neglect of the critical “Canada factor” in our social outcomes? And why aren’t Canadians trumpeting the positive social effect of their proximity? Is it because they want to maintain relative advantages and prevent possible overcrowding on the Canadian border? Isn’t it a bit suspicious that Vermont, New Hampshire, Maine and North Dakota are so underpopulated? That Potsdam is dwarfed by New York City?
Over at Living the Scientific Life an update on the quest to go to Antarctica. Turns out you can “reassign” your vote. Also, if you haven’t voted, please do. Again:
Voting ends at noon EDT on 30 September 2009, and the Official Quark Blogger will travel to Antarctica in February 2010 to blog about the experience, chronicling the action, the emotion, and the drama as this polar adventure unfolds.
A few months ago I pointed out that minorities don’t oppose gay marriage, blacks do. Specifically, there are sometimes assumptions that Hispanics are extremely religious Roman Catholics characterized by very socially conservative views. From what I have seen the data are of much more modest magnitude than what characterizations would suggest, but I thought it would be useful to put some numbers from the General Social Survey up. The years are from 2000-2008, when the “Hispanic” variable was being collected. First I separated into three categories, Non-Hispanics who were not black, which was a 95% white and 5% Asian sample. Then Hispanics (who were 1/3 white and 2/3 “Other”) and finally, blacks. Second, I decided to look at Non-Hispanic vs. Hispanic Roman Catholics. In this sample of Hispanics 2/3 were Roman Catholics.
Thomas Mailmund is going ape over chimps & humans again, Patterns of autosomal divergence between the human and chimpanzee genomes support an allopatric model of speciation. A review of a paper of the same name.
Interesting review paper on disease and Sub-Saharan African, Neglected Tropical Diseases in Sub-Saharan Africa: Review of Their Prevalence, Distribution, and Disease Burden:
The neglected tropical diseases (NTDs) are the most common conditions affecting the poorest 500 million people living in sub-Saharan Africa (SSA), and together produce a burden of disease that may be equivalent to up to one-half of SSA’s malaria disease burden and more than double that caused by tuberculosis. Approximately 85% of the NTD disease burden results from helminth infections. Hookworm infection occurs in almost half of SSA’s poorest people, including 40-50 million school-aged children and 7 million pregnant women in whom it is a leading cause of anemia. Schistosomiasis is the second most prevalent NTD after hookworm (192 million cases), accounting for 93% of the world’s number of cases and possibly associated with increased horizontal transmission of HIV/AIDS. Lymphatic filariasis (46-51 million cases) and onchocerciasis (37 million cases) are also widespread in SSA, each disease representing a significant cause of disability and reduction in the region’s agricultural productivity. There is a dearth of information on Africa’s non-helminth NTDs. The protozoan infections, human African trypanosomiasis and visceral leishmaniasis, affect almost 100,000 people, primarily in areas of conflict in SSA where they cause high mortality, and where trachoma is the most prevalent bacterial NTD (30 million cases). However, there are little or no data on some very important protozoan infections, e.g., amebiasis and toxoplasmosis; bacterial infections, e.g., typhoid fever and non-typhoidal salmonellosis, the tick-borne bacterial zoonoses, and non-tuberculosis mycobaterial infections; and arboviral infections. Thus, the overall burden of Africa’s NTDs may be severely underestimated. A full assessment is an important step for disease control priorities, particularly in Nigeria and the Democratic Republic of Congo, where the greatest number of NTDs may occur.
Sub-Saharan African has about 12% of the world’s population, so keep that in mind when viewing this table from the paper:
I saw Thirst this weekend, a Korean film about a Catholic priest turned vampire. I was expecting strangeness, but it was really strange. The female lead, Kim Ok-bin gave a pretty good performance that I found very memorable. My friend who I watched the film with wondered if Asians produced really strange films, but my own suspicion is that there’s a selection bias in terms of the types of “foreign films” which arrive to American shores. After all, what’s the comparative advantage of sappy Korean melodramas when we have so many of our own? In regards to special effects driven movies I doubt anyone can compete with Hollywood. So it has to be “art house” productions which trade on pushing the envelope combined with exotic locale. Or at least that’s my working model, would be happy to be informed by those “in the know”….
Anthropology.net points me to a new paper, Convergent genetic linkage and associations to language, speech and reading measures in families of probands with Specific Language Impairment:
We analyzed genetic linkage and association of measures of language, speech and reading phenotypes to candidate regions in a single set of families ascertained for SLI. Sib-pair and family-based analyses were carried out for candidate gene loci for Reading Disability (RD) on chromosomes 1p36, 3p12-q13, 6p22, and 15q21, and the speech-language candidate region on 7q31 in a sample of 322 participants ascertained for Specific Language Impairment (SLI). Replication or suggestive replication of linkage was obtained in all of these regions, but the evidence suggests that the genetic influences may not be identical for the three domains. In particular, linkage analysis replicated the influence of genes on chromosome 6p for all three domains, but association analysis indicated that only one of the candidate genes for reading disability, KIAA0319, had a strong effect on language phenotypes. The findings are consistent with a multiple gene model of the comorbidity between language impairments and reading disability and have implications for neurocognitive developmental models and maturational processes.
Right, there isn’t a “language gene” (sorry FOXP2). Language is a complex phenotype dependent on a lot of genes which can be “broken” in a lot of different ways. Though since verbal fluency (or, verbal IQ) varies quite a bit, if not basal verbal competency, there are likely many genes which shape how well we can wield language.
Cite: Journal of Neurodevelopmental Disorders, August 25, 2009, DOI: 10.1007/s11689-009-9031-x
Since I see p-ter hasn’t posted on this, in Science, Coat Variation in the Domestic Dog Is Governed by Variants in Three Genes:
Coat color and type are essential characteristics of domestic dog breeds. While the genetic basis of coat color has been well characterized, relatively little is known about the genes influencing coat growth pattern, length, and curl. We performed genome-wide association studies of more than 1000 dogs from 80 domestic breeds to identify genes associated with canine fur phenotypes. Taking advantage of both inter- and intrabreed variability, we identified distinct mutations in three genes, RSPO2, FGF5, and KRT71 (encoding R-spondin-2, fibroblast growth factor-5 and keratin-71, respectively), which together account for the majority of coat phenotypes in purebred dogs in the United States. This work illustrates that an array of varied and seemingly complex phenotypes can be reduced to the combinatorial effects of only a few genes.
See ScienceDaily for summary. This will help us cure cancer! OK, probably not, but hopefully perhaps we might get toward understanding hair form beyond EDAR.