A gene family is a set of several similar genes, formed by duplication of a single original gene, and generally with similar biochemical functions. One such family are the genes for human haemoglobin subunits; the ten genes are in two clusters on different chromosomes, called the α-globin and β-globin loci.
Genes are categorized into families based on shared nucleotide or protein sequences. Phylogenetic techniques can be used as a more rigorous test. The positions of exons within the coding sequence can be used to infer common ancestry. Knowing the sequence of the protein encoded by a gene can allow researchers to apply methods that find similarities among protein sequences that provide more information than similarities or differences among DNA sequences. Furthermore, knowledge of the protein's secondary structure gives further information about ancestry, since the organization of secondary structural elements presumably would be conserved even if the amino acid sequence changes considerably. These methods often rely upon predictions based upon the DNA sequence.
The expansion or contraction of gene families along a specific lineage can be due to chance, or can be the result of natural selection. To distinguish between these two cases is often difficult in practice. Recent work uses a combination of statistical models and algorithmic techniques to detect gene families that are under the effect of natural selection.
Other articles related to "gene family, family":
... RhoGDI2 (ARHGDIB) is part of a family of three members RhoGDI1, RhoGDI2 (also known as RhoGDIB, D4-GDI or Ly-GDI) and RhoGDI3 ... RhoGDI1 is expressed in many organs and is the best studied member of the family ...
Famous quotes containing the word family:
“Because its not only that a child is inseparable from the family in which he lives, but that the lives of families are determined by the community in which they live and the cultural tradition from which they come.”
—Bernice Weissbourd (20th century)