The gene pool of a species is all of the genes in the genome, including all the different variants of each gene.
Mutations can affect the gene pool of a population by increasing the number of different alleles available
The relative frequency of a particular allele in a population is called the allele frequency. If a mutation results in an advantageous feature, the allele will be selected for and so increase in frequency in the population. If the mutation is disadvantageous, natural selection will sometimes result in its removal from the gene pool.
A disadvantageous allele in one set of environmental may become an advantageous allele if conditions change. The change in allele frequency due to natural selection may lead to a new species
The genetic variation within a population is an important measure of biological health and well-being - without variation, a population is vulnerable
Scientists look at the proportion of a population which is heterozygous for a given feature. When the DNA is analysed, only one band will appear if the organism is a homozygote. For heterozygotes, two bands appear, one for each allele. This can be used to calculate a heterozygosity index for the particular DNA sequence. A high heterozygosity index reflex a high level of genetic variation and a potentially healthy population
Heterozygosity index = number of heterozygotes/number of individuals in a population
