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Promiscuous Primates Have Better Immune Systems

May 11, 2010

Sort of…

A recent study published in Evolution looked at correlations between sexual promiscuity and the evolution of genes involved in fighting disease:

[…] We found that immunity genes evolve faster in more promiscuous species, but only for a subset of genes that interact closely with pathogens. We also observed a significantly greater proportion of branches under positive selection in the more promiscuous species[…] These results suggest that mating system has influenced the evolution of some immunity genes in primates, possibly due to increased risk of acquiring sexually transmitted diseases in species with higher levels of promiscuity.

This is a correlative study, so it doesn’t necessarily¬†draw a line of causation from one to the other, but it makes sense. Other studies have shown that behaviors increasing exposure to disease (like living in larger groups) also increase the rate of evolution of genes involved in immunity. More exposure to disease = more selective pressure on your immune system.

But this is an evolutionary effect – don’t sleep around trying to cure your cold…

2 Comments leave one →
  1. May 13, 2010 7:51 am

    Would you explain deeper about promiscuous species? What it is?


    • kevbonham permalink*
      May 26, 2010 4:29 am

      It basically just indicates how much the females in a species sleep around. Some primate species have high fidelity – the females have relatively few mates throughout their lives. Gorillas, for instance, have troops of females “governed” by a single, dominant male. The leadership of the group may change, and there may be some covert breeding on the side with lower ranked males, but there is a high rate of sexual fidelity.

      Other primate species evidently have more of a free-love attitude, and these species show a strong influence of natural selection on the genes of their immune system.

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