Nevin Manimala Statistics

A Simple Evolutionary Model of Genetic Robustness After Gene Duplication

J Mol Evol. 2022 Aug 1. doi: 10.1007/s00239-022-10065-1. Online ahead of print.


When a dispensable gene is duplicated (referred to the ancestral dispensability denoted by O+), genetic buffering and duplicate compensation together maintain the duplicate redundancy, whereas duplicate compensation is the only mechanism when an essential gene is duplicated (referred to the ancestral essentiality denoted by O). To investigate these evolutionary scenarios of genetic robustness, I formulated a simple mixture model for analyzing duplicate pairs with one of the following states: double dispensable (DD), semi-dispensable (one dispensable one essential, DE), or double essential (EE). This model was applied to the yeast duplicate pairs from a whole-genome duplication (WGD) occurred about 100 million years ago (mya), and the mouse duplicate pairs from a WGD occurred about more than 500 mya. Both case studies revealed that the proportion of essentiality for those duplicates with ancestral essentiality [PE(O)] was much higher than that for those with ancestral dispensability [PE(O+)]. While it was negligible in the yeast duplicate pairs, PE(O+) (about 20%) was shown statistically significant in the mouse duplicate pairs. These findings, together, support the hypothesis that both sub-functionalization and neo-functionalization may play some roles after gene duplication, though the former may be much faster than the later.

PMID:35913597 | DOI:10.1007/s00239-022-10065-1

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