Something old, something new: Evolution and the structural divergence of duplicate genes
(PhysOrg.com) -- Gene duplications are arguably the driving force of organismal evolution and if they survive, such duplicate genes will diverge in both regulatory and coding genomic regions. Coding divergences, in turn, can be caused by nucleotide substitutions or exon-intron structural changes. (Exons are DNA bases that are transcribed into mRNA and eventually code for amino acids in proteins. Introns are DNA bases found between exons, but which are not transcribed.) Scientists have had limited knowledge in the latter case until recently, when researchers at the Institute of Botany of the Chinese Academy of Sciences investigated structural divergences during the evolution of duplicate and nonduplicate genes. They found that such structural divergences are very common in duplicate gene evolution, and have resulted from three primary causes exon/intron gain/loss, exonization/pseudoexonization (where an intronic or intergenic sequence becomes exonic, or vice versa), and insertion/deletion each contributing differently to structural...