2R hypothesis

The 2R hypothesis or Ohno's hypothesis, first proposed by Susumu Ohno in 1970,[1] is a hypothesis that the genomes of the early vertebrate lineage underwent two whole genome duplications, and thus modern vertebrate genomes reflect paleopolyploidy. The name derives from the 2 rounds of duplication originally hypothesized by Ohno, but refined in a 1994 version, and the term 2R hypothesis was probably coined in 1999. Variations in the number and timings of genome duplications typically still are referred to as examples of the 2R hypothesis.[2]

The 2R hypothesis has been the subject of much research and controversy; however, with growing support from genome data, including the human genome, the balance of opinion has shifted strongly in favour of support for the hypothesis. According to Karsten Hokamp, Aoife McLysaght and Kenneth H. Wolfe,[2] the version of the genome duplication hypothesis from which 2R hypothesis takes its name appears in Holland et al.[3] and the term was coined by Austin L. Hughes.[4]

  1. ^ Ohno, Susumu (1970). Evolution by Gene Duplication. London: Allen and Unwin, ISBN 0-04-575015-7.
  2. ^ a b Hokamp, K; McLysaght, A; Wolfe, KH (2003). "The 2R hypothesis and the human genome sequence". Journal of Structural and Functional Genomics. 3 (1–4): 95–110. doi:10.1023/A:1022661917301. PMID 12836689. S2CID 18856088.
  3. ^ Holland, PW; Garcia-Fernàndez, J; Williams, NA; Sidow, A (1994). "Gene duplications and the origins of vertebrate development". Development. Supplement: 125–33. PMID 7579513.
  4. ^ Hughes, Austin L. (1999). "Phylogenies of developmentally important proteins do not support the hypothesis of two rounds of genome duplication early in vertebrate history". Journal of Molecular Evolution. 48 (5): 565–76. Bibcode:1999JMolE..48..565H. doi:10.1007/PL00006499. PMID 10198122. S2CID 24897399.