Zoology · Ch 6 — Evolution
Gene Flow
Gene Flow
Gene flow is the movement of alleles between populations, occurring either through the movement of gametes (e.g. pollen) or through the physical movement of individuals into (immigration) or out of (emigration) a population. Organisms or gametes entering a population may carry alleles that are entirely new to that population, or may simply carry existing alleles in different relative proportions than the population already has, and in either case this changes the recipient population's allele frequencies without requiring any birth, death or selection to occur. Because it can rapidly introduce or redistribute genetic variation across otherwise separate populations, gene flow can act as a strong and fast-acting agent of evolutionary change (Fig. 6.8), and in practice it also wor …
What this figure shows. The diagram is labelled 'Migration' and shows a cluster of beetle icons of genotype AA on one side moving, via drawn arrows, into a second population made up mostly of aa genotype beetle icons. The combined group after migration shows a mix of AA and aa icons together in the same population, illustrating that individuals (or their gametes) crossing from one population into another physically carry alleles with them — here introducing the A allele into a population that previously consisted mainly of aa individuals — and so change that recipient …