Why a gene can vanish by pure luck: genetic drift
30seconds
Two versions of a gene start at 50% each. Neither is better, yet in a small population one will vanish by pure chance and the other will take over. This is genetic drift: each generation is a random sample of the last, and a small sample rarely mirrors it.
Run twenty populations at once, shrink or grow them, and change the starting share to see how population size decides who gets stuck, from fruit flies in bottles to an island that remembers one storm.
Deep dive · 5 min
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