Though not biologically related, friends are as “related” as fourth cousins, sharing about 1% of genes. That is【B1】___1 a study, published from the University of California and Yale University in the Proceedings of the National Academy of Sciences, has【B2】___

The study is a genome-wide analysis conducted【B3】___1, 932 unique subjects which【B4】pairs of unrelated friends and unrelated strangers. The same people were used in both【B5】___

While 1 % may seem【B6】___, it is not so to a geneticist. As James Fowler, professor of medical genetics at UC San Diego, says,“Most people do not even【B7】their fourth cousins but somehow manage to select as friends the people who【B8】___our kin.”

The study【B9】___found that the genes for smell were something shared in friends but not genes for immunity. Why this similarity exists in smell genes is difficult to explain, for now. 【B10】, as the team suggests,it draws us to similar environments but there is more【B11】it. There could be many mechanisms working together that【B12】us in choosing genetically similar friends【B13】“functional kinship” of being friends with【B14】___!

One of the remarkable findings of the study was that the similar genes seem to be evolving 【B15】___than other genes. Studying this could help【B16】why human evolution picked pace in the last 30,000 years, with social environment being a major【B17】___factor.

The findings do not simply explain people’s【B18】___to befriend those of similar【B19】backgrounds, say the researchers. Though all the subjects were drawn from a population of European extraction, care was taken to【B20】___that all subjects, friends and strangers, were taken from the same population.

【B17】