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Friendship and Natural Selection - Coggle Diagram
Friendship and Natural Selection
Abstract
Humans form social ties which is uncommon in other species
These social ties could be based off genotypes
Genotypes can be homophilic and heterophlilic
A synergistic fitness advantage may be present for forming social ties
Introduction
Friendship is a fundamental characteristic of humans
Friendships are formed based off phenotypic similarity
Genes have been linked to positive correlation when forming friendships
4 reasons for homophiliy in genes
Environmental influence on phenotype because of genotype
Likeness to one another "Birds of a Feather"
Geography
Third party selection by environment
Experiment
Conducted a genome-wide association
study (GWAS)
Used data from the Framingham Heart Study analyzed
Analyzed SNPs in several unique subjects who are in friendship pairs
Calculated the kinship coefficient
Positive values indicated that genotypes are
positively correlated
To eliminate the possibility that the results were influenced by distant relatives, kinship was less than or equal to 0
Prevented false positive by conducting a "strangers" GWAS
Discussion
Dozens or hundreds of genetic pathways form the basis of correlation in specific genotypes
Olfactory transduction pathway is significantly overrepresented
Friends tend to
have genotypes that yield similar senses of smell
Linoleic acid metabolism system is significantly overrepresented
Suggests that friends have different genotypes
for coping with infection
Conducted same analysis for strangers and did not find any overrepresented genes
Positive and significant relationship
in the friends GWAS for homophilic SNPs
Genotypes that humans share with friend tend to be under recent seelction than other genes
Conclusion
Homophily on genes
related to linoleic acid metabolism are unclear
The human evolutionary environment is not limited to
the physical or biological environment
Includes social environment
The genes of others might modify the
fitness advantages of one’s own genes
Communication is the key to synergy
Homophiliy evolved once we started interacting socially with unrelated individuals