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No evidence for disassortative mating based on HLA in a small-scale, endogamous population
Gillian L Meeks1, Brooke Scelza2, Katherine M Kichula3
1Graduate Program in Integrative Genetics and Genomics, University of California Davis, Davis, 95616, CA, USA.
Biorxiv : the Preprint Server for Biology
|July 14, 2025
Summary
Mate choice in the Himba population does not show a preference for Human Leukocyte Antigen (HLA) dissimilarity. This suggests HLA diversity, not disassortative mating, may drive immune gene evolution.
Area of Science:
- Human evolutionary genetics
- Immunogenetics
- Population genetics
Background:
- Evidence for disassortative mating based on Human Leukocyte Antigen (HLA) genes is inconsistent across populations.
- Previous studies on HLA- تتزاوج have yielded mixed results, with some suggesting assortative mating in cosmopolitan populations.
- Few studies have examined HLA-based mate choice in small-scale, endogamous groups relevant to human evolutionary history.
Purpose of the Study:
- To investigate whether HLA dissimilarity influences mate choice among the Himba, an endogamous group in Namibia.
- To compare HLA genetic profiles in chosen (love/informal) versus arranged partnerships.
- To assess potential fitness benefits of offspring genotypes related to HLA-based pathogen binding.
Main Methods:
- Targeted sequencing of eight classical HLA genes in 366 individuals.
- Recording of self-reported partnership types and informal partnerships.
- Analysis of HLA dissimilarity in 249 known partnerships (chosen vs. arranged).
- Evaluation of HLA-based pathogen binding affinities for potential offspring.
Main Results:
- No significant difference in HLA dissimilarity was found between chosen and arranged partnerships.
- Partnership types did not differ from a random distribution of HLA dissimilarity.
- No differences in HLA-based pathogen binding affinities were observed between arranged and chosen partners.
- Extensive haplotype sharing in the HLA region suggests recent positive selection.
Conclusions:
- Mate choice among the Himba does not appear to be driven by maximizing HLA dissimilarity.
- High background HLA diversity in the Himba may limit the fitness benefits of disassortative mating.
- Fluctuating positive selection may play a more significant role in maintaining HLA polymorphism than disassortative mating.
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