Lynch M, Bürger R, Butcher D, Gabriel W
Department of Biology, University of Oregon, Eugene 97403.
J Hered. 1993 Sep-Oct;84(5):339-44. doi: 10.1093/oxfordjournals.jhered.a111354.
Loss of fitness due to the accumulation of deleterious mutations appears to be inevitable in small, obligately asexual populations, as these are incapable of reconstituting highly fit genotypes by recombination or back mutation. The cumulative buildup of such mutations is expected to lead to an eventual reduction in population size, and this facilitates the chance accumulation of future mutations. This synergistic interaction between population size reduction and mutation accumulation leads to an extinction process known as the mutational meltdown, and provides a powerful explanation for the rarity of obligate asexuality. We give an overview of the theory of the mutational meltdown, showing how the process depends on the demographic properties of a population, the properties of mutations, and the relationship between fitness and number of mutations incurred.
在小型专性无性繁殖种群中，由于有害突变的积累导致的适应性丧失似乎是不可避免的，因为这些种群无法通过重组或回复突变来重建高度适应的基因型。预计此类突变的累积会导致种群规模最终减小，这又增加了未来突变偶然积累的可能性。种群规模减小与突变积累之间的这种协同相互作用会导致一种被称为“突变崩溃”的灭绝过程，并为专性无性繁殖的罕见性提供了有力解释。我们概述了突变崩溃理论，展示了该过程如何依赖于种群的人口统计学特征、突变的特性，以及适应性与所产生突变数量之间的关系。
