evolutionduplications

Evolutionary duplications refer to the creation of additional copies of genetic material during evolution, producing paralogous genes or genomic regions that can accumulate mutations independently. These duplications arise by several mechanisms, including unequal crossing over during meiosis, DNA replication errors, retrotransposition, and whole-genome duplication (WGD). Duplications range from single-gene tandem duplications to large-scale segmental duplications and complete genome duplications, the latter especially common in plants and some animal lineages.

Their evolutionary significance lies in providing raw material for genetic innovation. Duplicate genes can acquire new functions (neofunctionalization), partition ancestral functions between copies (subfunctionalization), or become nonfunctional through degradation (pseudogenization). Changes in regulatory regions can also cause divergent expression patterns even without coding changes. Duplication can affect gene dosage and network architecture, with consequences for fitness.

Detection and study: Researchers identify paralogs via sequence similarity, conserved synteny, and phylogenetic analysis; Ks (synonymous substitution) values help estimate duplication ages. Comparative genomics can reveal ancient WGD events and lineage-specific expansions.

Examples: The early vertebrate lineage is proposed to have undergone two rounds of whole-genome duplication (2R), with a unique teleost-specific third round (3R). Plants show widespread polyploidy, contributing to diversity. Gene-family expansion through tandem duplications is common in immune genes in vertebrates and in many plant metabolic gene families.