Angelina Jolie + The Superficial + the genome = Genetics & Health

Over at Genetics & Health Lei is commenting on the genetic character of Shiloh Jolie-Pitt, and referencing an old post of mine on this topic re: genetics. It is all pretty amusing, but, here is a prediction:

The level of spontaneous abortion should be increasing in modern populations

"Spontaneous abortions" are the half of pregnancies which naturally terminate without the woman ever knowing. It is often said that modern populations are subject to relaxed selection, that is, the genetically less fit can, and do, reproduce at a healthy level. Over time this should increase the genetic load upon the population and the frequency of deleterious alleles increases...but does it? The point I'm trying to make is that there is still the bottleneck of implantation and early embryonic development at work. The reality is human embryos are subject to extremely high rates of chromosomal abnormalities and other assorted mutations, trisomy 21, which leads to Down Syndrome, is actually a rather a mild form of karyotypic malformation. Most of the others are lethal and result in spontaneous termination. The point is that the human population is rather large, I'm not that scared of a mutational meltdown. Additionally, we don't really know the exact frequency of spontaneous abortion because of its nature, so we probably don't know if the rates are increasing to purge the gene pool.

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"The point is that the human population is rather large, I'm not that scared of a mutational meltdown."

How do we identify the populations in which deleterious mutations are more common?
How do we identify the less fit? If you partialed out some lifestyle variables from low SES pops, how much would they vary in fitness vis-a-vis high SES ones, incidence of disease? The population is still stratified for class(SES), IQ(covariance w/SES), etc, & assortative pairings are common, I believe.
How do we find the high risk populations?

By Rietzsche Boknekht (not verified) on 07 Jun 2006 #permalink

The level of spontaneous abortion should be increasing in modern populations

If other things are more or less equal. But if globalisation is currently increasing the amount of outbreeding in human populations, it will be a while before the genetic load catches up. So the level could go down, then up - unless there is some slight outbreeding depression operating at the same time as well.

looks like dominance effects, so the heritability is in the broad sense here, not in the more normal narrow sense usage :)

p.s. finns suck!