Genetic variability

Genetic variability is either the presence of, or the generation of, genetic differences.
It is defined as "the formation of individuals differing in genotype, or the presence of genotypically different individuals, in contrast to environmentally induced differences which, as a rule, cause only temporary, nonheritable changes of the phenotype". Genetic variability in a population is important for biodiversity.
Causes.
There are many sources of genetic variability in a population:
Factors that decrease genetic variability.
There are many sources that decrease genetic variability in a population: