It looks as if sex evolved because it's in the interest of genes to constantly be re-combined   self interest not always in company with the same others   may want to be er mixing themselves up, so they launch themselves  in continually different combinations, and this presumably  each gene   what, what, what is happening is a constant filtering process all the time, by means of which natural selection is working on basically random changes in the   final point I want to make and that's 