Defining Gene Flow
Gene flow, also known as migration or allele flow, is the transfer of genetic material (in the form of alleles) from one population to another of the same species. This movement of genes is a fundamental mechanism of evolution that alters the genetic composition of populations.
Section 2: The Mechanism of Gene Flow
Gene flow occurs when individuals or their gametes (e.g., pollen from plants or sperm from aquatic animals) move from one location to another and successfully reproduce in the new population. This process introduces new alleles into the receiving population's gene pool and can remove alleles from the source population.
Section 3: A Practical Example
Imagine a population of brown beetles living on one side of a highway and a population of green beetles on the other. If a few brown beetles manage to cross the highway and reproduce with the green beetles, they introduce the 'brown' allele into the green beetle population. This movement and subsequent reproduction is an example of gene flow.
Section 4: Importance in Evolution
Gene flow is significant because it can increase the genetic variation within a population by introducing new alleles. Conversely, it tends to reduce the genetic differences between populations, making them more similar over time. This can prevent or slow down speciation by counteracting the effects of natural selection and genetic drift that would otherwise cause populations to diverge.