Answer :
Final answer:
Gene flow is the main factor responsible for the genetic change described in the scenario involving domesticated reindeer and migrating caribou.
Explanation:
Gene flow is the factor that led to the change in the scenario described. When domesticated reindeer escape and mate with migrating caribou, adding alleles for short legs and tame behavior, this process is a result of gene flow, which is the flow of alleles in and out of a population due to the migration of individuals or gametes.
Founder effect and non-random mating are also mechanisms that could lead to genetic changes in a population, but in the given scenario, the introduction of new alleles through mating with migrating caribou is primarily driven by gene flow.
Gene flow plays a crucial role in introducing genetic variation into populations and can impact the allele frequencies in a population over time.
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