Tagged: assortative mating

The Sooner We Are All Mongrels, the Better

E.O. Wilson charges across the is-ought barrier with a zeal undiminished by his advancing years and promotes genetic diversity as a moral good in The Social Conquest of Earth:

Perhaps it is time…to adopt a new ethic of racial and hereditary variation, one that places value on the whole of diversity rather than on the differences composing the diversity. It would give proper measure to our species’ genetic variation as an asset, prized for the adaptability it provides all of us during an increasingly uncertain future. Humanity is strengthened by a broad portfolio of genes that can generate new talents, additional resistance to diseases, and perhaps even new ways of seeing reality. For scientific as well as moral reasons, we should learn to promote human biological diversity for its own sake instead of using it to justify prejudice and conflict.

This follows an analysis of the relative genetic differences between various racial groups of humans, concluding that subsaharan Africa contains the highest genetic diversity among human groups. Yet almost everything in our social and biological history suggests that we have formed social structures specifically to prevent out-breeding and limit the expansion of our genetic pool. This has always been a thorny subject for selfish genetics: why risk pairing your alleles with unknowns guessed at through proximal sexual clues like body symmetry or the quality of giant peacock tails? The risk of outbreeding is apparently lower than the risk of diverse infectious agents according to a common current theory, but we also see culture as overriding even the strongest outbreeding motivation by imposing mating rules based on familial and tribal power struggles. At the worst, we even see inbreeding depression in populations that consolidate power through close marriages (look at the sex-linked defect lineages in European royal families) or through long religious prohibitions on marrying outside of relatively small populations of the faithful. A few years back there was even a suggestion promoted in the popular press that autism might be caused by assortative mating by geeks and computer programmers.

We should all be latte colored or at least mongrels. The alternative is too much like what happens to highly bred dogs:

Hundreds of different dog breeds have now been established although the majority have only come into existence in the last two centuries. These breeds have largely been generated by the selection of gross phenotypic attributes particularly suited for work or decorative purposes, many being encoded by single gene mutations. A consequence of such a severe selection and inbreeding history is that many breeds have come from a relatively restricted gene pool.

As expected, the mongrels have the highest number of different alleles (22 out of 30 possible alleles tested).

But back to Wilson and the is-ought barrier: should we be obligated to promote genetic diversity across the species? There are several arguments embedded in Wilson’s statements that we can unpack:

  1. The species, as a whole, will be more likely to “generate new talents, [resist] diseases, and [create new ways of seeing reality].”
  2. Diversity will not be seen as a source of difference and conflict, and therefore will reduce conflicts based on differences.

So, for (1), can we really see this as a moral good for any individual or couple? Taken to the extreme, the guidance would suggest preferential mating with those most genetically diverse or at least different from you. Stuck on the “is” side of the barrier, however, there are also the standard proximate drivers for sexual attraction and the more “global” motivation for promoting species-level diversity might override those drivers. The net effect would probably be insignificant, however, because we can assume that affairs of the heart would kick in and minimize the impact. Still, it is a bit of an odd moral good to contemplate in its rawest form. More clarifying, however, might be the argument that immigration policies can have a similar effect over time because propinquity is the mother of all desire.