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Friendship and natural selection - Coggle Diagram
Friendship and natural selection
homophilic genome
positive corrolation between genotypes of friends
such as olfactory and linoleic genes
possible reasons
retain friendships with individuals with similar genotypes and terminate friendships with individuals with dissimilar genotypes
seek out environment with people with similar phenotype (and therefore similar genotype)
more likley to have similar ancestory to individuals in geographic proximity
selected into environments with similar people
more common and stronger selection than heterophilic genotypes
heterophilic genome
such as immune systemgenes
possible reasons
intentionally befriending individuals with different traits
difference in traits might be preferred in some environments
negative correlation between genotypes of friends
experiment to test homophily in pairs of friends
average genome relationship of friends is that of fourth cousins which is significantly closer than average relatedness of random strangers
genome analysis between pairs of friends and pairs of strangers in a sample of individuals
created a "friendship score" successfully able to predict likelihood of two individuals from a sample being friends or strangers
Christakis, N.A. Fowler, J.H. 2014. Friendship and natural selection. PNAS. 111 (supplement_3) 10796-10801
https://doi.org/10.1073/pnas.1400825111
general conclusions
interaction with unrelated individuals might be contributing to human evolution
could be evidence of a kin detection system in humans
experiment to test if homophilic SNPs are favored by selection
determine if certain SNPs have become more common over 30,000 years
SNPs between friends that are most homophilic had higher likelihood of positive evolutionary selection
SNPs between strangers that are most homophilic did not significant likelihood of positive evolutionary selection