by S. Mar­vin Fried­man — Thanks to the ex­ten­sive re­search of the past ten years, we've be­come aware that many prokary­otic en­dosym­bionts and ha­bit­ual in­tra­cel­lu­lar pathogens have un­der­gone genome re­duc­tion over evo­lu­tion­ary time. Char­ac­ter­is­tic of this process, termed re­duc­tive con­ver­gent evo­lu­tion, is the dis­card­ing of genes in­volved in meta­bolic path­ways and reg­u­la­tory func­tions that have…