Pseudogene rescue: an adaptive mechanism of codon reassignment |
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Authors: | L J JOHNSON |
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Institution: | School of Biological Sciences, University of Reading, Reading, UK |
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Abstract: | Alterations to the genetic code – codon reassignments – have occurred many times in life’s history, despite the fact that genomes are coadapted to their genetic codes and therefore alterations are likely to be maladaptive. A potential mechanism for adaptive codon reassignment, which could trigger either a temporary period of codon ambiguity or a permanent genetic code change, is the reactivation of a pseudogene by a nonsense suppressor mutant transfer RNA. I examine the population genetics of each stage of this process and find that pseudogene rescue is plausible and also readily explains some features of extant variability in genetic codes. |
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Keywords: | early evolution genetic code nonsense suppression theory |
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