Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. Allele frequency is the proportion of all copies of a gene that is made up of a particular gene variant. In other words, it is the number of copies of a particular allele divided by the number of copies of all alleles at the genetic place in a population. It can be expressed for example as a percentage. In population genetics, allele frequencies are used to depict the amount of genetic diversity at the individual, population, and species level. It is also the relative proportion of all alleles of a gene that are of a designed type. Given the following: a particular locus on a chromosome and the gene occupying that locus ,a population of N individuals carrying n loci in each of their somatic cells, different alleles of the gene exist, one allele exists in a copies then the allele frequency is the fraction or percentage of all the occurrences of that locusthat is occupied by a given allele and the frequency of one of the alleles is a/(n N).