A possible mechanism in convergent evolution

Abstract

It has been shown in laboratory experiments that viruses can transfer DNA from the host cell to other cells and even to those of another species. In nature such transfers could facilitate convergent evolution. Studied cases of convergent evolution indicate that a gene might be successfully transferred to another species to produce a similar phenotypic effect as frequently as once per 1–10 ma and the effects of gene transfer on evolution in general are likely to be considerable. There are many constraints on the cases of convergent evolution that might be considered as possible examples of gene transfer. First, both co-occurrence in space and time of the taxa in question and presence of complete reproductive isolation must be assessed. Further, both the limited space available in a virus particle and the necessity that the transferred DNA functions well in both mitosis and meiosis in heterozygotic individuals indicate that only rather short pieces of DNA would be expected to be transferred. This limits the possible effects of any gene transfer. Examples of convergent evolution in five Siluro-Devonian conodont lineages are briefly presented and assessed in terms of possible mechanisms of convergence.