Gene duplication

Process in genetics that describes the duplication of a specific gene or a specific DNA segment on one of the two sister chromatids created during replication by unequal crossing over. A distinction is made here between partial and complete gene duplication.

Gene duplications are the starting point for the formation of gene families. As a rule, the mutations cannot be corrected by their own repair mechanisms and often lead to congenital defects due to the severe alteration of the gene sequence. However, gene duplication is also considered to be an essential mechanism of evolution.

The genes created by duplication are called paralogous genes, indicating the relationship between two different members of a gene family within a species, while the same genes found in different species are called orthologous genes.

One duplication that has previously been identified as potentially contributing to IBD (IBD-inflammatory bowel disease) risk concerns the IL2RA/IL15R loci. It has recently been shown that a microduplication of this locus can predispose to very early-onset IBD (Dirvanskyte P et al. 2023).

1. Dirvanskyte P et al. (2023) Chromosomal Numerical Aberrations and Rare Copy Number Variation in Patients with Inflammatory Bowel Disease. J Crohns Colitis 17:49-60.
2. Marwaha AK et al. (2022) A Chromosomal Duplication Encompassing Interleukin-33 Causes a Novel Hyper IgE Phenotype Characterized by Eosinophilic Esophagitis and Generalized Autoimmunity. Gastroenterology 163:510-513.e3.