Whole gene duplication

The remaining mutations are mostly larger lesions and comprise only 7% of human mutations. These include whole gene duplications and deletions, SSR expansions (e.g., trinucleotide repeat expansions), gene rearrangements (e.g., B-and T-cell gene rearrangements), and complex polymorphic loci related to health and disease (e.g., HLA). 

Fig. 1. Schematics of evolutionary mechanisms of domain swapping in nature. Multifunctional proteins arise from the fusion of the genes coding for individual enzymes. Often the individual domains of multifunctional proteins catalyze successive steps in metabolic pathways. In tandem duplication, a gene is duplicated and the 3 end of one copy is fused in-frame to the 5 end of the second copy. In domain recruitment, a functional unit (whole gene or gene fragment) from one gene is either inserted within or fused to an end of a second gene. Circular permuted genes are believed to arise via tandem duplication followed by introduction of new start and stop codons (Ponting el at, 1995).

Robinson-Rechavi, M., O. Marchand, H. Escriva and V. Laudet. An ancestral whole-genome duplication may not have been responsible for the abundance of duplicated fish genes. Curr. Biol. 11 R458-R459, 2001. 

Scannell, D. R., Frank, A. L., Conant, G. C., Bymek, R, Woolflt, M., Wolfe, K. H. (2007). Independent sorting-out of thousands of duplicated gene pairs in two yeast species descended from a whole-genome duplication. Proceedings of the National Academy of Sciences of the United States of America, 104, 8397-8402. 

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