∞ generated and posted on 2016.08.28 ∞

Specific, physical location on a chromosome that a gene is found.


Figure legend: A genetic locus is the location of a gene on a chromosome. Here chromosomes are rendered as sister chromatids, though note that in reality homologous chromosomes do not line up like this, as sister chromatids, but instead as sister chromatid pairs. That is, the chromosome-like shape have been provided in this figure for purely aesthetic reasons! The stars represent equivalent genes found at equivalent loci on the two chromosomes. These genes may or may not differ in terms of their DNA sequence, with differences in sequence implying heterozygosity and lack of differences implying homozygosity. Such differences among genes are known as allelic differences.

The number of types of alleles that can be found at a given locus can range from one to many, with two or more constituting within a population what is known as a polymorphism. The number of types of alleles that can be found at the same locus within a single, diploid individual ranges from one up only to two, however.