The differences in sets of alleles between individuals in a population are called genetic variation. This variation is the raw material for evolution, as it provides the basis for natural selection to act upon.

Here are some more specific terms related to genetic variation:

* Allelic variation: Differences in the specific versions of genes (alleles) that individuals possess.

* Genotypic variation: Differences in the combinations of alleles that individuals have.

* Phenotypic variation: Differences in the observable characteristics of individuals, which are often influenced by their genotype.

Genetic variation can arise from various sources, including:

* Mutations: Changes in the DNA sequence that introduce new alleles.

* Gene flow: The movement of alleles between populations through migration.

* Recombination: The shuffling of alleles during sexual reproduction.

The level of genetic variation within a population can have significant implications for its ability to adapt to changing environments.