Genomic ancestry linked to mate selection, study shows

This image shows the coding region in a segment of eukaryotic DNA. Credit: National Human Genome Research Institute

Genetic ancestry, as well as facial characteristics, may play an important part in who we select as mates, according to an analysis from UC San Francisco, Microsoft Research, Harvard, UC Berkeley and Tel Aviv University.

Researchers used population genomics and quantitative social sciences to gauge the relatedness of parents in a study of asthma in Mexican and Puerto Rican children.

They found that the parents tended to choose partners with a similar mix of ancestry to their own, a phenomenon known as assortative mating. In the case of Mexicans, that meant having a similar proportion of mostly European and Native American ancestry, with some genomic heritage from Africa. For Puerto Ricans, that meant having similar amounts of European and African ancestry, with some Native American.

The average mix was similar enough to make the couples equivalent to between third and fourth cousins, a degree of closeness that may have implications for the perpetuation of some genetic diseases but also could have health benefits. A study done in Iceland, for example, found that the most fertile couples were about as closely related as fourth cousins.

Among the Puerto Rican, but not the Mexican couples, the researchers also found that parents had similar genes associated with . The strength of the ancestry assortment in both groups was stronger than education assortment, a powerful factor in mate selection that has been well documented.

The researchers said their findings could affect a wide range of disciplines that employ population genomics.

"To avoid mathematical complexities, population and medical geneticists typically assume that people choose their mates randomly when modeling everything from demographic history to the diseases in a population," said Noah Zaitlen, PhD, an assistant professor of medicine at UCSF. "We now have evidence that these choices may not be random at all, and we should incorporate this new understanding to more accurately model human history and improve our understanding of the genetic basis of disease."

The researchers said it was important to keep in mind that they only found associations between factors like ancestry and partner selection, not evidence that one was influencing the other, and they warned that some of the factors they measured, like the genes known to be involved in facial development and genomic ancestry could be entangled with one another, or related to other factors they did not measure, like culture and religion.

Given their subjects' mixed European, Native American and African , the researchers said their participants' high genomic diversity is likely to have contributed to a wider array of facial characteristics and may have magnified the effect of their tendency to choose similar-looking partners. The same thing could be happening in more homogenous populations, like European Americans, they said, but it could be harder to detect.

"To the extent that people assort based on physical appearance and cultural background, both factors can be correlated with individuals' genomic ancestries," said James Zou, PhD, a postdoctoral researcher with Microsoft Research in Cambridge, Mass. "In Mexican and Puerto Rican communities, there is greater diversity in individuals' genomic ancestries, compared to European Americans. If this is reflected in a greater diversity of physical appearances, this can contribute to stronger assortment."

The tendency to find a mate with a similar genetic background, a form of assortative mating, could also help perpetuate genetic diseases. In Puerto Ricans, who have founder mutations from both the Spaniards who colonized the island and the Native American women who bore their children, the researchers estimated that assortative mating could increase the prevalence of recessive diseases by 2 to 14 percent after 10 generations of mixing. And the researchers said it may help explain the high prevalence of certain diseases like asthma and Hermansky Pudlak Syndrome among Puerto Ricans.

The researchers did not genotype the parents of the 2,757 trios they studied - about 1,246 of which were Mexican trios and 1,511 Puerto Rican trios - but rather inferred their relatedness through their children, who were genotyped. They also used a smaller study of 489 trios, in which both parents and children were genotyped, to validate their findings.

The researchers said more analyses should be done in other groups, to flesh out the implications of what they found.

"We need to understand how these patterns of assortment vary across diverse populations, as well, with finer geographic sampling of individuals," said Sriram Sankararaman, PhD, a postdoctoral fellow at Harvard Medical School.

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Asthma risk varies with ethnic ancestry among Latinos

More information: Genetic and socioeconomic study of mate choice in Latinos reveals novel assortment patterns, PNAS,
Citation: Genomic ancestry linked to mate selection, study shows (2015, October 19) retrieved 20 July 2019 from
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Oct 19, 2015
MHC–disassortative mating preferences reversed by cross–fostering http://www.ncbi.n...1689202/ is one of the clearest early links to nutrient-dependent pheromone-controlled ecological speciation in species from microbes to humans.

Ecological speciation has since been linked across all vertebrate biodiversity by a single nutrient-dependent amino acid substitution. Achiral glycine appears to protects organized genomes from virus-driven genomic entropy by linking food odors to the pheromone-controlled GnRH-modulated physiology of reproduction via chromosomal rearrangements.

For example, see: Estrogen Receptor Alpha as a Mediator of Life-History Trade-offs http://icb.oxford...abstract

Oct 19, 2015
See also:

The conserved molecular mechanisms of assortative mating extend from all invertebrates to all vertebrates via what is currently known about the role of microRNAs and adhesion proteins.

Did everyone else like their joke about: "Genetic ancestry, as well as facial characteristics, may play an important part in who we select as mates."

Facial characteristics are not linked from all invertebrates to mate choice in all vertebrates.

Oct 19, 2015
"Facial characteristics are not linked from all invertebrates to mate choice in all vertebrates."

I'm glad I wasn't drinking anything when I read that. Hilarious.

Oct 20, 2015
Thanks. It's only hilarious to those who realize the difference between ridiculous theories about mutations and evolution compared to facts about RNA-mediated cell type differentiation.

As a biologically uninformed science idiot, what did you think was so funny? In retrospect, I think they might be serious about linking facial characteristics to mate choice outside the context of an atoms to ecosystems model of cell type differentiation in all living genera.

Oct 20, 2015
"Genetic and socioeconomic study of mate choice in Latinos reveals novel assortment patterns"


"Nonrandom mating in human populations reflects a confluence of socioeconomic and biological factors. In this paper, we integrate population genomics with quantitative social sciences to address fundamental questions about mate selection. In Mexican and Puerto Rican couples, we find that partners share more similar genomic ancestries, which is characterized as the fractions of genome that come from European, Native American, and African ancestries, than random pairs of individuals from the same community. Our analysis shows that this similarity cannot be explained by the individuals' socioeconomic factors alone. Our mathematical model illustrates how assortative mating can increase the prevalence of recessive diseases in Latino populations"

Another epic reading comprehension fail by JVK.

Oct 20, 2015
Mathematical models may or may not reveal aspects of sexually differentiation cell types, which are RNA-mediated. When they reveal what we detailed about the immune system in our 1996 Hormones and Behavior review, they reveal the reading comprehension problem among inbred evolutionary theorists.

An Xist-activating antisense RNA required for X-chromosome inactivation (2015)

From our 1996 review: "Genomic-imprinting is also manifest in specific parts of the X-inactivation region's related XIST gene. Here male- and female-specific methyl-group patterns participate in X-inactivation in females and also in the preferential inactivation of the paternal X in human placentae of female concepti (Harrison, 1989; Monk, 1995). This process indicates that tissues of the early conceptus can sense and react differentially to epigenetic sexual dimorphisms...http://www.hawaii...ion.html

Oct 20, 2015
From my 2013 review: Nutrient-dependent/pheromone-controlled adaptive evolution: a model.

Exceprt: "Two additional recent reports link substitution of the amino acid alanine for the amino acid valine (Grossman et al., 2013) to nutrient-dependent pheromone-controlled adaptive evolution. The alanine substitution for valine does not appear to be under any selection pressure in mice. The cause-and-effect relationship was established in mice by comparing the effects of the alanine, which is under selection pressure in humans, via its substitution for valine in mice (Kamberov et al., 2013)."

Apparently, Harvard reseachers are not taught anything about pattern recognition, which links metabolic networks to genetic networks in species from microbes to man. They reported their findings in terms of mutations and evolution / pseudoscientific nonsense.

Oct 20, 2015
See also: Sperm RNAs Transmit Stress

My comment: "Nutrient stress and social stress act via the innate immune system and cause the suppression of the immune system that links the proliferation of viruses to transgenerational epigenetic inheritance via everything currently known about microRNAs and adhesion proteins."

Oct 20, 2015
See also: Sex Differences in the Brain

Let's try to intelligently discuss how mutations might be linked to transgenerational epigenetic inheritance of sex differences in the brain, shall we.

Any biologically uninformed science idiot can start that discussion and tell us when they first learned that "Facial characteristics are not linked from all invertebrates to mate choice in all vertebrates."

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