A gene family is a group of genes that share important characteristics. In many cases, genes in a family share a similar sequence of DNA building blocks (nucleotides). These genes provide instructions for making products (such as proteins) that have a similar structure or function. In other cases, dissimilar genes are grouped together in a family because proteins produced from these genes work together as a unit or participate in the same process.
Classifying individual genes into families helps researchers describe how genes are related to each other. Researchers can use gene families to predict the function of newly identified genes based on their similarity to known genes. Similarities among genes in a family can also be used to predict where and when a specific gene is active (expressed). Additionally, gene families may provide clues for identifying genes that are involved in particular diseases.
Sometimes not enough is known about a gene to assign it to an established family. In other cases, genes may fit into more than one family. No formal guidelines define the criteria for grouping genes together. Classification systems for genes continue to evolve as scientists learn more about the structure and function of genes and the relationships between them.
For more information about gene families
Genetics Home Reference provides information about gene families including a brief description of each gene family and a list of the genes included in the family.
The HUGO Gene Nomenclature Committee (HGNC) has classified many human genes into families. Each grouping is given a name and symbol, and contains a table of the genes in that family.
The textbook Human Molecular Genetics (second edition, 1999) provides background information on human gene families.
The Gene Ontology database lists the protein products of genes by their location within the cell (cellular component), biological process, and molecular function.
The Reactome database classifies the protein products of genes based on their participation in specific biological pathways. For example, this resource provides tables of genes involved in controlled cell death (apoptosis), cell division, and DNA repair.
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