Genfamilien

Genfamilien, or gene families, are sets of related genes within an organism’s genome that share a measurable level of sequence similarity and often a related biological function. They originate primarily through gene duplication events, after which duplicated copies diverge in sequence and sometimes in function. They are identified by comparative genomics methods that detect conserved domains and sequence homology.

Gene families vary in size from a few members to hundreds. They can be organized in tandem clusters or dispersed across chromosomes, and may include functional genes and pseudogenes. Evolutionary processes such as tandem or segmental duplications and whole-genome duplications shape their repertoires. Paralogs arise within a species from duplications, while orthologs reflect speciation.

Examples include the globin family, with alpha and beta globin genes; the HOX (homeobox) developmental gene family; olfactory receptor gene families; and various immune receptor gene families in vertebrates. These families illustrate different patterns of expansion and functional diversification.

Functions and evolution: gene family members may retain ancestral roles, acquire new ones (neofunctionalization), or split original functions (subfunctionalization). Functional redundancy can occur, while some duplicates become nonfunctional pseudogenes.

Analysis and relevance: researchers study gene families using phylogenetics, synteny, and domain architecture to understand genome evolution and functional predictions. Gene families are central to annotating genomes, interpreting genetic variation, and exploring implications for health and disease, including copy-number variation and pharmacogenomics.