Nature of Deleterious Mutation Load in Drosophila
AUTOR(ES)
Keightley, P. D.
RESUMO
Much population genetics and evolution theory depends on knowledge of genomic mutation rates and distributions of mutation effects for fitness, but most information comes from a few mutation accumulation experiments in Drosophila in which replicated chromosomes are sheltered from natural selection by a balancer chromosome. I show here that data from these experiments imply the existence of a large class of minor viability mutations with approximately equivalent effects. However, analysis of the distribution of viabilities of chromosomes exposed to EMS mutagenesis reveals a qualitatively different distribution of effects lacking such a minor effects class. A possible explanation for this difference is that transposable element insertions, a common class of spontaneous mutation event in Drosophila, frequently generate minor viability effects. This explanation would imply that current estimates of deleterious mutation rates are not generally applicable in evolutionary models, as transposition rates vary widely. Alternatively, much of the apparent decline in viability under spontaneous mutation accumulation could have been nonmutational, perhaps due to selective improvement of balancer chromosomes. This explanation accords well with the data and implies a spontaneous mutation rate for viability two orders of magnitude lower than previously assumed, with most mutation load attributable to major effects.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=1207746Documentos Relacionados
- New estimates of the rates and effects of mildly deleterious mutation in Drosophila melanogaster
- Spontaneous deleterious mutation in Arabidopsis thaliana
- Estimation of Deleterious-Mutation Parameters in Natural Populations
- Deleterious mutation prediction in the secondary structure of RNAs
- The Evolution of Selective Advantage in a Deleterious Mutation