Geeniperhe

Geeniperhe, Finnish for "gene family," refers to a group of related genes within a genome that share a common ancestral gene and often retain similar sequences and functions. Gene families arise primarily through gene duplication events, followed by divergence that can lead to novel functions or specialization. Members are called paralogs within the same species; corresponding genes in different species are orthologs.

Gene families are classified by sequence similarity, conserved domains, and the organization of the genomic locus. Large families may expand through tandem duplication or dispersed duplication across chromosomes. Evolutionary processes shaping gene families include neofunctionalization, subfunctionalization, and gene conversion, sometimes contributing to concerted evolution that keeps gene copies similar in sequence.

Prominent examples include the globin gene family (hemoglobin and myoglobin), Hox gene clusters (developmental patterning), and olfactory receptor gene families (odor detection). In the immune system, diverse receptor families such as MHC genes or KIR illustrate extensive diversification. The size and composition of a gene family can vary between species and over evolutionary time, reflecting different selective pressures and ecological needs.

In research and medicine, gene-family analysis aids genome annotation, functional prediction, and the study of evolutionary relationships. Pseudogenes—nonfunctional relatives within a gene family—can influence interpretation of data. Annotation and phylogenetic methods help distinguish paralogs from orthologs and resolve complex family histories, informing studies from developmental biology to disease mechanisms.