Final answer:
Genetic variance is the variety of alleles and genotypes found within a population, contributing to phenotypic differences among individuals. It is influenced by a population's genetic structure, environment, and other factors. High heritability indicates that natural selection can significantly act on this genetic variation.
Step-by-step explanation:
Genetic variance refers to the diversity of alleles and genotypes within a population. This variance is a critical aspect of a population's genetic makeup as it contributes to the phenotypic differences among individuals. Genetic variance is influenced by factors such as genetic structure, the environment, and diet composition. Population variation, on the other hand, is concerned with the distribution of phenotypes in a population, as exemplified by the array of fur colors and patterns in domestic dogs.
Heritability is the proportion of this phenotypic variation that can be due to genetic differences among individuals. The higher the heritability, the more a population's phenotypic variation is subjected to natural selection and other evolutionary forces. Increasing genetic variance within a controlled breeding environment is a common strategy to maintain phenotypic diversity and to minimize the risks associated with inbreeding.