Phenotypic Uncoupling

A small note on admixture.

I have probably written about this before, but let us consider a population A that contains low levels of "exotic" admixture from population X, from some time ago. Over the centuries, independent assortment and recombination will continuously uncouple, to a considerable extent, the association between alleles that code for X-like phenotypes and those other alleles that connote X ancestry, but which may not necessarily have any (obvious) phenotypic implications.

Now, if one were to consider large numbers of A – and certainly the population as a whole (compared to others) - there still may well be a general and approximate correlation between X ancestry and X phenotypes. But at the individual level, for individual As – or even small groups of As – the association will be to a significant extent uncoupled, so one can find an A who looks X but with less X ancestry than an A who looks more typically A, and vice versa.

Also, given the same processes of independent assortment and recombination, one would likely find individuals and families of A that have higher-than-normal concentrations of alleles encoding X phenotypic traits. This may well explain, e.g., extremely dark and strange looking Euro-swarthoids, or the Bromstad/Bjork types who look like they should be eating with chopsticks. One may also find individuals and families with more X ancestral markers and that observation may or may not be associated with, or uncoupled from, the X phenotypic alleles.

The bottom line is that with a small sample size “N” the correspondence between trace ancestry and phenotype (and let’s assume we are talking about physical appearance here) may be tenuous at best.  As “N” increases, the association may become stronger, but won’t be as perfect as it was immediately after the admixture event.

And the longer ago that event occurred, the more difficult it will be to detect, as X haplotypes are broken up, X-like genetic structure is disrupted – particularly in the cases where X traits (ancestry, phenotype) is due different allele frequencies compared to A, rather than to unique alleles (the latter case could still be detected over time, but truly unique ethnoracial alleles are relatively rare).

Now, these are the kinds of subtleties that will of course not find a home (“it’s sophistry, sophistry – although I couldn’t tell you why!”) within a “movement” that believes there is a line drawn in Europe (apparently painted on the ground) that, on one side, we find individuals and populations who are racially pure to the misty beginnings of time forever and ever amen, and, on the other side, we find individuals and populations who are cringing mongrelized subhumans.  All you have to do is step over that line and the difference is obvious – just don’t step on the line until the paint is dry or it will have to be repainted once again.