November 22, 2009
Mixed Genetic Ancestry And Mating

Mexicans and Puerto Ricans of mixed races tend to marry those of similar racial mix ratios.

A team led by Neil Risch and Esteban González Burchard of the University of California, San Francisco, took DNA samples from married couples in Mexican and Puerto Rican populations, examining around 100 genetic markers from across the genome. From these markers, the researchers were able to discern the proportions of Native American, European and African ancestry for each person.

They found that within Mexican populations, people tended to pick partners with similar proportions of Native American and European ancestry, while in Puerto Rican populations couples had paired up based on their shared balance of European and African ancestry.

Some easily measured physical characteristics do not appear to explain all of the mate selection results. How about sense of smell?

Quite how our DNA influences our desires remains mysterious. Risch and his colleagues did not find that geography or socio-economic status could explain the ancestral influence on romance, and factors like hair, eye and skin colour individually only had a minor role. According to Burchard, "Certainly physical characteristics, such as skin pigment, hair texture, eye color, and other physical features are correlated with ancestry and are likely to be factors in mate selection. However, the spouse correlation for these traits and the correlation of these traits with ancestry were actually below what would be required to fully explain the phenomenon".

Socioeconomic profile did not explain the mating patterns as well as genetic markers. I'd like to know what causes these results. I can imagine a number of genetic mechanisms by which mating preferences would track with genetic markers. Among the potential explanations that come to mind:

  • Genetic sequences might code for preferences for facial shapes, skin color, and other visible attributes.
  • Parental facial features and other physical features get imprinted on a baby and that causes the baby to prefer others who have similar features. So the brain doesn't directly code for preferences but (rather like Konrad Lorenz's geese) we are sensitive toward imprinting at some stage of development.
  • Genetic sequences might code for personality and cognitive attributes that track with the genetic markers. People might be attracted to similar personalities.
  • Settling. Preferences might not differ but competition results in like marrying like.

I would like to see studies done that use a combination of genetic marker comparison and pictures of people to see to what extent physical attraction tracks with similarity of genetic markers. To distinguish between the first two explanations above children of transracial adoptions could be included in the study.

Has much imprinting research been done about human attraction across races?

Share |      Randall Parker, 2009 November 22 06:54 PM  Brain Beauty


Comments
Gergen said at November 22, 2009 7:56 PM:

Aren't these researchers connected to Phil Jones at the East Anglia University Climate Research Unit? There were some interesting emails concerning these particular researchers in the bunch that were hacked from CRU.
You may want to check it out and add more information to this posting.

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