Gene family

Gene family is a group of related genes that share common characteristics. These genes are often formed by duplication of a single original gene, and then diverged through mutations. The genes in a gene family may be functionally very similar or somewhat dissimilar, depending on the rate at which the gene is duplicated.

Overview

A gene family is a set of several similar genes, formed by duplication of a single original gene, and generally with similar biochemical functions. They are categorized in a hierarchical manner, based on sequence homology and the mechanism of gene duplication. If a gene family is large, it is often divided into subfamilies.

Formation

Gene families are formed by the process of gene duplication and divergence, where a gene is duplicated and the duplicate copy undergoes mutation and acquires new functions. This process is a primary source of evolutionary novelty.

Classification

Gene families can be classified into two broad categories, depending on their mechanism of formation. These are:

• Tandem gene duplication: This occurs when a gene is duplicated and the duplicate copy is inserted next to the original gene in the genome. This is the most common mechanism of gene family formation.
• Segmental gene duplication: This occurs when a large segment of a chromosome, containing several genes, is duplicated.

Examples

Some examples of gene families include the Hox gene family, the globin gene family, and the homeobox gene family. These gene families play crucial roles in development, oxygen transport, and DNA-binding, respectively.

See also

• Gene duplication
• Gene expression
• Genome
• Molecular evolution

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