Alleelifrekvenssit

Alleelifrekvenssit, also known as allele frequencies, refer to the relative proportion of a specific allele within a population's gene pool. An allele is a variant form of a gene. For example, a gene that determines eye color might have different alleles for blue, brown, or green eyes. The allele frequency is calculated by dividing the number of copies of a specific allele by the total number of copies of all alleles for that gene in the population.

These frequencies are crucial in the study of population genetics and evolutionary biology. Changes in allele frequencies over time are the very definition of evolution. Factors such as mutation, gene flow (migration), genetic drift (random chance events), and natural selection can all influence allele frequencies. For instance, if an allele provides a survival or reproductive advantage, its frequency is likely to increase in the population over generations due to natural selection. Conversely, a disadvantageous allele may decrease in frequency.

Allele frequencies are typically expressed as a decimal or a percentage. For a gene with only two alleles, say A and a, their frequencies are represented as p and q, respectively, where p + q = 1. These frequencies are fundamental for understanding genetic diversity within populations and how populations change and adapt over time. They are also used in fields like conservation biology to assess the genetic health of endangered species and in medical genetics to understand the predisposition to certain diseases.