A
gene family is a set of
homologous genes within one organism. A
gene cluster is part of a gene family. A gene cluster is a group of two or more
genes found within an organism's
DNA that encode for similar
polypeptides, or
proteins, which collectively share a generalized function and are often located within a few thousand base pairs of each other. The size of gene clusters can vary significantly, from a few genes to several hundred genes. Portions of the DNA sequence of each gene within a gene cluster are found to be identical; however, the resulting protein of each gene is distinctive from the resulting protein of another gene within the cluster. Genes found in a gene cluster may be observed near one another on the same
chromosome or on different, but
homologous chromosomes. An example of a gene cluster is the
Hox gene, which is made up of eight genes and is part of the
Homeobox gene family.