PMID: 17099057;PMCID: PMC1808353;Abstract:
A possible origin of novel coding sequences is the removal of stop codons, leading to the inclusion of 3′ untranslated regions (3′ UTRs) within genes. We classified changes in the position of stop codons in closely related Saccharomyces species and in a mouse/rat comparison as either additions to or subtractions from coding regions. In both cases, the position of stop codons is highly labile, with more subtractions than additions found. The subtraction bias may be balanced by the input of new coding regions through gene duplication. Saccharomyces shows less stop codon lability than rodents, probably due to greater selective constraint. A higher proportion of 3′ UTR incorporation events preserve frame in Saccharomyces. This higher proportion is consistent with the action of the [PSI+] prion as an evolutionary capacitor to facilitate 3′ UTR incorporation in yeast. © 2006 The Authors.
PMID: 20598394;PMCID: PMC3198833;Abstract:
Why isn't random variation always deleterious? Are there factors that sometimes make adaptation easier? Biological systems are extraordinarily robust to perturbation by mutations, recombination and the environment. It has been proposed that this robustness might make them more evolvable. Robustness to mutation allows genetic variation to accumulate in a cryptic state. Switching mechanisms known as evolutionary capacitors mean that the amount of heritable phenotypic variation available can be correlated to the degree of stress and hence to the novelty of the environment and remaining potential for adaptation. There have been two somewhat separate literatures relating robustness to evolvability. One has focused on molecular phenotypes and new mutations, the other on morphology and cryptic genetic variation. Here, we review both literatures, and show that the true distinction is whether recombination rates are high or low. In both cases, the evidence supports the claim that robustness promotes evolvability. © 2010 Elsevier Ltd.
PMID: 24228631;PMCID: PMC3849687;
