Genregionduplicationer

Genregionduplicationer are structural variations in which a segment of DNA containing one or more genes is copied, yielding an extra genomic copy. Duplications can be tandem (adjacent on the chromosome) or dispersed to different locations, and they contribute to copy-number variation within and between species.

Several mechanisms generate these duplications, including unequal crossing over during meiosis, replication-based processes such as fork stalling and template switching, and retrotransposition. The genome’s segmental duplications, also called low-copy repeats, predispose to non-allelic homologous recombination that creates or enlarges duplicated segments.

Duplication outcomes vary: increased gene dosage can alter traits; duplicate genes may retain the original function, diverge to new functions (neofunctionalization), partition ancestral functions (subfunctionalization), or become pseudogenes. Duplications drive gene-family expansion and contribute to evolutionary novelty as well as disease susceptibility when dosage-sensitive genes are affected.

Detection and study rely on genomic techniques such as comparative genomics, array-based comparative genomic hybridization (array CGH), SNP arrays, and whole-genome sequencing. Analysis often uses read depth, paired-end mapping, and split-read approaches to identify copy-number variations and resolve their breakpoints.

Notable examples of gene-region duplications include the expansion of the amylase gene cluster in certain human populations, duplication of olfactory receptor gene families, and human-specific duplications such as SRGAP2 that have been proposed to influence brain development.

In evolutionary biology, genregionduplicationer are regarded as a major engine of genomic innovation, enabling new gene functions and regulatory landscapes while contributing to diversity in morphology and physiology across life.