HumancultureplaysaroleinnaturalselectionByHYPERLINK"http://topics.nytimes.com/top/reference/timestopics/people/w/nicholas_wade/index.html?inline=nyt-per"\o"MoreArticlesbyNicholasWade"NICHOLASWADEPublished:March1,2010TheNewYorkTimesAswithanyotherspecies,humanpopulationsareshapedbytheusualforcesofnaturalselection,likefamine,diseaseorclimate.Anewforceisnowcomingintofocus.Itisonewithasurprisingimplication—thatforthelast20,000yearsorso,peoplehaveinadvertentlybeenshapingtheirownevolution.Theforceishumanculture,broadlydefinedasanylearnedbehavior,includingtechnology.Theevidenceofitsactivityisthemoresurprisingbecauseculturehaslongseemedtoplayjusttheoppositerole.Biologistshaveseenitasashieldthatprotectspeoplefromthefullforceofotherselectivepressures,sinceclothesandshelterdullthebiteofcoldandfarminghelpsbuildsurplusestorideoutfamine.Becauseofthisbufferingaction,culturewasthoughttohavebluntedtherateofhumanevolution,orevenbroughtittoahalt,inthedistantpast.Manybiologistsarenowseeingtheroleofcultureinaquitedifferentlight.Althoughitdoesshieldpeoplefromotherforces,cultureitselfseemstobeapowerfulforceofnaturalselection.Peopleadaptgeneticallytosustainedculturalchanges,likenewdiets.Andthisinteractionworksmorequicklythanotherselectiveforces,“leadingsomepractitionerstoarguethatgene-cultureco-evolutioncouldbethedominantmodeofhumanevolution,”KevinN.LalandandcolleagueswroteintheFebruaryissueofHYPERLINK"http://www.nature.com/nrg/journal/v11/n2/abs/nrg2734.html"\o"Readtheabstract."NatureReviewsGenetics.Dr.LalandisanevolutionarybiologistattheUniversityofSt.AndrewsinScotland.Theideathatgenesandcultureco-evolvehasbeenaroundforseveraldecadesbuthasstartedtowinconvertsonlyrecently.Twoleadingproponents,RobertBoydoftheHYPERLINK"http://topics.nytimes.com/topics/reference/timestopics/organizations/u/university_of_california/index.html?inline=nyt-org"\o"MorearticlesabouttheUniversityofCalifornia."UniversityofCalifornia,LosAngeles,andPeterJ.RichersonoftheHYPERLINK"http://topics.nytimes.