On the causes of evolutionary transition:transversion bias

Arlin Stoltzfus; Ryan W. Norris

The results presented here also prompt the question of how the lore that transitions are conservative was estabished. In a survey of the literature, we found that, when the . CC-BY 4.0 International license is made available under a The copyright holder for this preprint (which was not peer-reviewed) is the author/funder. It . https://doi.org/10.1101/027722 doi: bioRxiv preprint alleged conservativeness of transitions is attributed to a source, the source is often Zhang (2000) , or early works such as Fitch (1967) , Grantham (1974) or Vogel and Kopun (1977) . Grantham does not directly address this issue, but a genetic-code-based calculation shows that the mean Grantham distance for transition-mediated replacements is lower than that for transversions, e.g., as indicated in Table 2 of Xia, et al (1998) . The study by Vogel and Kopun is often cited as evidence for the conservative transitions hypothesis, because they present a calculation that, for 3 different biochemical measures, suggests that transitions are more conservative. Nevertheless, Vogel and Kopun themselves favored a mutational explanation (see hypothesis 3 on p.