Final answer:
Recombination reduces linkage disequilibrium by mixing genetic material during sexual reproduction, which creates new allele combinations and decreases non-random associations of alleles. This process contributes to genetic diversity, particularly in allopatric speciation where isolated populations evolve differently.
Step-by-step explanation:
By breaking up overrepresented haplotypes and creating new ones, recombination reduces linkage disequilibrium. Recombination is a vital genetic process where genetic material is mixed during sexual reproduction, leading to the creation of offspring with combinations of traits that differ from both parents. This process serves to reduce the phenomenon known as linkage disequilibrium, where certain alleles are found together more often than would be expected by chance alone. Recombination essentially decreases this non-random association of alleles by allowing for the shuffling of genetic material.
In the context of speciation and gene flow, recombination has a crucial role. For instance, in allopatric speciation, the separation of a population into geographically isolated groups allows for different evolutionary paths. Recombination within these isolated groups contributes to the genetic diversity by producing new allele combinations. Meanwhile, gene flow, or the movement of alleles across populations, can reintroduce diversity and reduce genetic differences that may have emerged due to isolation. If gene flow does not occur, the separated populations may continue to diverge ultimately leading to speciation.