Migration

• Migration causes changes in the allele frequencies of both the population the individuals leave and the population they join.
• Immigration - individuals migrating into a population. This can add new alleles to a population, increasing the population genetic biodiversity
• Emigration - individuals migrating out of a population can remove alleles, reducing genetic biodiversity
• If populations are large, migration might have little or no effect on allele frequency, but in small populations it can have a great effect on allele frequency.