6.2.4: Increase in genetic diversity: mutation

A mutation is a change in DNA, and thus creates a new allele and increases genetic diversity. The frequency at which this occurs is small, but differs between species. In humans the mutation rate is estimated at 10^-5 per gene per meiosis (generation). Mutations tend to occur especially on specific regions on the genome: mutation hotspots. A lot of mutations are deleterious. A dominant mutation often results in mortality (abortion) of the embryo. Recessive mutations hide in heterozygous state and spread through the population. They only come to expression in homozygous state. Some mutations are harmless, and some are positive. Positive mutations will be subject of selection and thus may increase in frequency more efficiently. Not all mutations result in a change in function of the gene, these are called silent mutations. Many of the SNP (single nucleotide polymorphism) are such silent mutations and are used as genetic markers.