Alleles

An allele is a variant form of a gene that is present at a specific locus on a chromosome. In a heterozygous individual, two different alleles can be present at a locus, one inherited from each parent. Some alleles are dominant, meaning they are expressed in the phenotype, while others are recessive and will only be expressed in the phenotype when two copies of the recessive allele are present. Alleles are an important part of genetics, as allelic differences between individuals are responsible for the genetic variation within a population which provides the necessary diversity for natural selection to occur. Alleles are also of great importance in medicine and biotechnology as they can provide information about genetic diseases, allow for the development of treatments such as gene therapy, and let us understand how the makeup of an individual’s genome impacts their health.