On Cousinhood

            On Cousinhood

 

          Assured of your supremacy?

          Oh silly sibling, don’t be smug!

          For great and wide’s our family tree;

          Dear sister seaweed, brother bug!

 

        First cousins are those who share a grandparent; second cousins share a great-grandparent; in general Nth cousins share an great^(N-1)-grandparent; or in other words share a parent N+1 generations back.  Therefore siblings are zeroth cousins, and one is one’s own negative first cousin!

        For what value of N are all human beings Nth cousins? This is a matter of evolutionary history. The present human species is about 200,000 years old, and at about 20 years per generation, that comes to 10,000 generations; so I would guess that we are at most 10,000ths cousins of each other; and probably much less.  There is some genetic evidence of genetic bottlenecks in human prehistory; so I would guess that we are at most 7000th cousins of each other, probably much less.

        And what of other species? I found the following figures at the site   www.evogeneao.com

        chimp      =  240,000^th cousin

        gorilla        = 310,000^th cousin

        cat            =  27,000,000^th cousin

        cow          =  28,000,000^th cousin

        robin         = 170,000,000^th cousin

        frog          =  175,000,000^th cousin

        fish           =  195,000,000^th cousin

        snail           = 300,000,000^th cousin

        dragonfly  = 300,000,000^th cousin

        octopus  =   300,000,000^th cousin

        According to that website, one can’t properly define cousinhood for bacteria. If we did, then I suppose that we’d be zillionth cousins to redwood and mildew, for some absurdly high value of zillion.

        In any case, it’s nice to have such a big and talented family.  Blessings, cousins!