The researchers suggest in the study that the presence of genes that contribute to trait variability might help explain the presence of common diseases. Much as having a variable Y aided the model organism in their simulation in the long run but were detrimental in a static environment, variability in traits such as the ability to control blood sugar could have helped human ancestors survive to the present but become detrimental in the current environment.This makes sense. The more variation that is present in any given generation, the better the chance for which some alleles will be selected positively. Evolution thrives on variability. This is why founder effect can cripple a population.
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