Mhlawumbe sonke sesizwile igama elithi "ilotho yemfuzo", kodwa wake wacabanga ngempela ngomthelela wangempela walolu daba? Kwa-DNA ME sisebenza eduze nazo zonke izinto eziphathelene nemfuzo, ngakho namuhla ngiyanibingelela ukuthi nihlanganyele ekucwaningeni isihloko esihle sefilosofi esithi "Imvelo vs Ukukhuliswa" ukuze siqonde ukuthi impumelelo empilweni yethu ingakanani ngempela ixhumene nenhlanhla nje, nokuthi imizamo yethu eqinile ikhanya kangakanani lapho.
Ake siqale ekuqaleni kokuvuka kweHomo sapiens, cishe eminyakeni engu-600 000 edlule. Ezindaweni ezisemngceleni weNkathi Yeqhwa, okhokho bakho abazizwa "abakhishiwe" — bazizwa njengabancane abangena engxenyeni yomfula ebuswa abazala abake bazi zonke izivunguvungu nazo zonke izindlela ezimfishane: amaNeanderthal, azinzile njengelitshe, asebenza ngokumangalisayo nangempumelelo, futhi abe ngabantu ngokuphelele endleleni abahamba ngayo sengathi umhlaba uqobo useceleni kwabo. Ungaba nesibindi futhi ube nekhono kodwa uphinde wehluleke ngoba ukuphonsa kwakho sekwephuzile ngesigamu senkathi yenhliziyo, ngoba ubanda bubuze ukubamba kwakho, ngoba iphutha elilodwa kuyoba konke okudingekayo; ngaleso sikhathi, endaweni ethile emuva emlandweni wakho ngemva kokwahlukana nomugqa wamaNeanderthal, inhlanhla nje ijika i-coin encane kakhulu ku-TKTL1—i-arginine esikhundleni se-lysine—futhi akufiki ngomsindo, kufika njengengane esinda ngenhlanhla (ingenaso ifiva, ukudla okwanele, ubusika obubushelelezi obubodwa) isikhathi eside ngokwanele ukuze leyo shintsho lisabalale.
I-TKTL1 ingenye yalezo zimo ezibizwa ngokuthi "ushintsho oluncane nemiphumela emikhulu": emgudwini womuntu wanamuhla, kushintshwa i-amino acid eyodwa (i-arginine esikhundleni se-lysine yamaNeanderthal/yezikhathi zasendulo) okucatshangwa ukuthi kushukumisele ukuthuthukiswa kobuchopho besisu ukuba kwakhe ama-neuron amaningi e-cortex, ikakhulukazi ezindaweni zangaphambili. Ngokwempela, lokho bekungeke kwenze muntu abe hlakaniphile ngokushesha—kodwa bekungashintsha amathuba emincintiswaneni eseduze ngokuthuthukisa ukuhlela, ukuvumelanisa, nokufunda ngokwanele ukuthi, emizukulwaneni eminingi, abantu besimanje bavame ukudlula amaNeanderthal ngobuhlakani kunokuthi ngamandla.
Ama-dinosaur ayisihlekiso somkhathi sendaba ethi "ukuphenduka kwemali ye-TKTL1 enethamsanqa": awazange athole nje isikhathi sokuzivumelanisa, kodwa athola isikhathi esingaphezu kwengqondo—cishe iminyaka eyizigidi ezingama-165 njengezilwane ezibusayo emhlabeni—isikhathi eside kangangokuba uShakespeare wama-dinosaur wayengakwazi ukuqala "uHamlet, iNkosi yama-Hadrosaur," egxekwa abagxeki ngokuthi "kunezinkulumo eziningi zomuntu oyedwa," futhi eseneminyaka eyizigidi ezimbalwa eseleyo yokwenza kabusha itiyetha. Phakathi naleso sikhathi, ukukhethwa kwemvelo kwaba nemijikelezo engenamkhawulo yokubathuthukisa babe imishini yezinto eziphilayo—izivikelo, usayizi omkhulu, ukuzingela okusebenza ngokweqile, ochwepheshe abangajwayelekile—ngakho-ke uma "umsebenzi onzima + isikhathi" bekuyiqinisekiso lokuphila, bebengasazibusa umhlaba. Kodwa ukuguquka kwemvelo akuyona intaba; kuwumqhudelwano onezinguquko zemithetho ezingahleliwe, futhi ngolunye usuku ukuphenduka kwengqekembe okubanzi kweplanethi (ukungqubuzana kwe-asteroid nomthelela walo emkhathini) kwabhala kabusha imvelo ngokushesha kunalokho ukuzivumelanisa okungaphendula. Isifundo se-science-pop: inhlanhla encane ingasiza umgogodla uwine omunye ubusika (umoya wakho we-TKTL1), kodwa inhlanhla embi enkulu ingasusha iminyaka eyizigidi ezingama-165 yempumelelo ngendlela engathi kuwukushiya umhlaba ngokushesha—ishiya izinyoni ziyizodwa kuphela kwezidalwa ezifana nama-dinosaur ezisele esiteji.
Futhi yilokho okungakhululekile kule ndaba: akukaze kube 'onamandla kakhulu' ophumelela, kodwa kube ngulowo othole uchungechunge olufanele lwemiphumela emihle—ishintsho elincane lephrotheni elaphila isikhathi eside ngokwanele ukuze libe nomthelela, ubusika obungabulali osanda kuzalwa, isinqumo esisodwa esigweme umgodi ongafanele—futhi ama-dinosaur afakazela okuphambene nalokho, ukuthi iminyaka eyizigidi ezingama-165 yokubusa ingaphela ngenxa yokuphonswa okukodwa okubi okuvela ezulwini. Uma inhlanhla ingaqondisa ama-genome futhi isuse izimpucuko, khona-ke ukufunda i-DNA akuyona into yokuzilibazisa yomnyuziyamu; kuyindlela yokubona umehluko omncane okhula ngokuhamba kwesikhathi ngenkathi kusekhona isikhathi sokuthatha izinyathelo ngakho.