Ohno's dilemma: Evolution of new genes under continuous selection

@article{citeulike:1817764, abstract = {New genes with novel functions arise by duplication and divergence, but the process poses a problem. After duplication, an extra gene copy must rise to sufficiently high frequency in the population and remain free of common inactivating lesions long enough to acquire the rare mutations that provide a new selectable function. Maintaining a duplicated gene by selection for the original function would restrict the freedom to diverge. (We refer to this problem as Ohno's dilemma). A model is described by which selection continuously favors both maintenance of the duplicate copy and divergence of that copy from the parent gene. Before duplication, the original gene has a trace side activity (the innovation) in addition to its original function. When an altered ecological niche makes the minor innovation valuable, selection favors increases in its level (the amplification), which is most frequently conferred by increased dosage of the parent gene. Selection for the amplified minor function maintains the extra copies and raises the frequency of the amplification in the population. The same selection favors mutational improvement of any of the extra copies, which are not constrained to maintain their original function (the divergence). The rate of mutations (per genome) that improve the new function is increased by the multiplicity of target copies within a genome. Improvement of some copies relaxes selection on others and allows their loss by mutation (becoming pseudogenes). Ultimately one of the extra copies is able to provide all of the new activity. 10.1073/pnas.0707158104}, author = {Bergthorsson, Ulfar and Andersson, Dan I. and Roth, John R. }, citeulike-article-id = {1817764}, doi = {10.1073/pnas.0707158104}, journal = {Proceedings of the National Academy of Sciences}, keywords = {evolution, qualifier}, month = {October}, number = {43}, pages = {17004--17009}, posted-at = {2007-10-25 00:46:38}, priority = {3}, title = {Ohno's dilemma: Evolution of new genes under continuous selection}, url = {http://dx.doi.org/10.1073/pnas.0707158104}, volume = {104}, year = {2007} }

TY - JOUR ID - citeulike:1817764 L3 - citeulike-article-id:1817764 TI - Ohno's dilemma: Evolution of new genes under continuous selection JF - Proceedings of the National Academy of Sciences VL - 104 IS - 43 SP - 17004 EP - 17009 N2 - New genes with novel functions arise by duplication and divergence, but the process poses a problem. After duplication, an extra gene copy must rise to sufficiently high frequency in the population and remain free of common inactivating lesions long enough to acquire the rare mutations that provide a new selectable function. Maintaining a duplicated gene by selection for the original function would restrict the freedom to diverge. (We refer to this problem as Ohno's dilemma). A model is described by which selection continuously favors both maintenance of the duplicate copy and divergence of that copy from the parent gene. Before duplication, the original gene has a trace side activity (the innovation) in addition to its original function. When an altered ecological niche makes the minor innovation valuable, selection favors increases in its level (the amplification), which is most frequently conferred by increased dosage of the parent gene. Selection for the amplified minor function maintains the extra copies and raises the frequency of the amplification in the population. The same selection favors mutational improvement of any of the extra copies, which are not constrained to maintain their original function (the divergence). The rate of mutations (per genome) that improve the new function is increased by the multiplicity of target copies within a genome. Improvement of some copies relaxes selection on others and allows their loss by mutation (becoming pseudogenes). Ultimately one of the extra copies is able to provide all of the new activity. 10.1073/pnas.0707158104 KW - evolution KW - qualifier AU - Bergthorsson, Ulfar AU - Andersson, Dan AU - Roth, John PY - 2007/10/23/ UR - http://dx.doi.org/10.1073/pnas.0707158104 ER -