Mittwoch, 24. Januar 2007

Population bottleneck during "out of africa"

New hints for a population bottleneck concerning (anatomical modern) humans leaving the african continent were presented in "Annals of Human Genetics":

"... At the NF1 gene locus two clearly separated groups of haplotypes, corresponding to the two haplogroups described by us (Schmegner et al. 2005), are present in the European population and both Asian populations, but not in the African population. This argues against a population bottleneck during the immigration of the AMH into Europe, because a reduction to two NF1 gene lineages during this event would not have affected the Asian populations. At the chromosome 22 locus a different picture is obtained for the European and Asian populations, with no split into two clearly separated subgroups of haplotypes. The patterns for the two loci in the African population are quite similar. Therefore, if a population bottleneck is considered to explain the variability patterns, the HapMap data show that this bottleneck most probably occurred throughout the emigration of the AMH out of Africa. Recently signs of a population bottleneck in variability data obtained for a number of genomic loci in European and Asian populations, but not in African populations, were described and also led to the conclusion that this bottleneck occurred after the appearance of the AMH in Africa, and thus presumably during the emigration out of Africa (Harpending & Rogers, 2000; Balciuniene et al. 2001; Alonso & Armour, 2004; Marth et al. 2004; Stajich & Hahn, 2005; Voight et al. 2005)."
And for Europe only:
"Regarding demography, the most plausible explanation is the assumption of a severe bottleneck in the history of the European population: in the case of the chromosome 17 locus two ancient lineages passed this bottleneck; for the chromosome 22 locus it was only one ancient lineage."

Sonntag, 21. Januar 2007

Traditional egalitarian societies in transition

A new study in „Evolution and Human Behavior“ asks for the selection pressures put upon a traditional egalitarian society (in the Amazonian forest), that is in transition to become integrated into modern industrialized (Bolivian) society with its huge division of labour. They ask for the personal characteristics that make persons successful in the new economic environment. Their main concept is “patience” or: “the ability to delay gratification”.

Differences in this area, they write, “allow people to deal with disequilibrium and to use local resources better, thereby enhancing their inclusive fitness”. They have a lot of good thoughts and insights about all that but – it seems to me: the main problem is that their study is not informed by modern IQ-genetics. We know about modern societies that their social inequality and division of labour (between countries worldwide and inside of them) have a lot to do with IQ and that IQ has a lot to do with genetics. So it seems to me, that it could be also the personal IQ of a member of a traditional society that predisposes him or her to participate more or less in the new or in the traditional economic environment. For the old, traditional economic environment you do not need so much IQ as you need for the new economic environment. But alas, they have made good personal tests with their participants but no IQ-tests. They write:
“Once a society opens up to the market economy, one should see patient and impatient people sorting themselves into different groups (...) Patient people will sidle to schools, while the impatient will continue” to perform traditional ways of life, “BECAUSE people have to wait a long time to reap any returns to schooling.”
“Because”? Are young children (grades one to four) patiently in school “because” of rewards and gratifications later in life? I don’t think so at least not before puberty. I think at this point it becomes clear, that the concept of “the ability to delay gratification” cannot be the whole story. Are children successful in schools “because” of their patience or are they patient because they’re successful? I think, the latter is more plausible, but sure, personal characteristics like AHDS will have influences as well. But if you have good teachers – may be – those personal characteristics will not have so much influence - ? It would be interesting to separate IQ from other personal factors more precisely to estimate the factors that influences personal economic success instead of IQ. Surely there are more factors. But do we have about them as good and valid datas as about IQ?

Donnerstag, 18. Januar 2007


I'm running a Scienceblog in German but I like to broaden my readership and my partners for discussion. So I try to make this blog.

I have studied history, biology, philosophy and at the moment I'm mostly interested in all new trends in sociobiology and human genetics. Several years ago, I also have begun a dissertation in this area. At the moment I find myself mostly interested in the intellectual area around "Gene Expression" and around the interdisciplinary and comparative study of religion in the sense of Michael Blume.

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