Variations in a population of individuals are transmitted genetically from generation to generation. The genes that define the variety of traits of a species are inherited from the reproducing individuals in the population, and it is up to chance to determine which alleles, or which alternative forms of a gene, will come from which of the two parents.

Genetic recombination is the moment in sexual reproduction when the mother’s chromosomes pair up with the father’s. Some alleles will be inherited from the mother and others from the father.