engleski

Mutation accumulation in real branches: fitness assays for genomic deleterious mutation-rate and effect in large-statured plants

The genomic deleterious mutation rate and mean effect are central to the biology and evolution of all species. Large-statured plants such as trees are pre- dicted to have high mutation rates due to mitotic mutation and the absence of a sheltered germ line, but their size and generation time has hindered ge- netic study. We develop and test approaches for estimating deleterious mutation rates and effects from viability comparisons within the canopy of large-statured plants. Our methods, inspired by E.J. Klekowski, are a modification of the classic Bateman-Mukai mutation-accumulation experiment. Within a canopy, cell lin- eages accumulate mitotic mutations independently. Gametes or zygotes produced at more distal points by these cell lineages contain more mitotic mutations than at basal locations, and within-flower selfs contain more homozygous mutations than between-flower selfs. The resulting viability differences allow demonstration of lethal mutation with experiments similar in size to assays of genetic load, and allow estimates of the rate and effect of new mutations with moderate precision and bias similar to that of classic mutation-accumulation experiments in small- statured organisms. These methods open up new possibilities with the potential to provide valuable new insights into the evolutionary genetics of plants.

mutation accumulation; autogamy; geitonogamy; plant crown

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