New estimates of the rates and effects of mildly deleterious mutation in Drosophila melanogaster
New estimates of the rates and effects of mildly deleterious mutation in Drosophila melanogaster
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DOI：
10.1073/pnas.96.2.574
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发表时间：
1999-01-19
影响因子：
11.1
通讯作者：
Nuzhdin, SV
中科院分区：
文献类型：
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作者：
Fry, JD;Keightley, PD;Nuzhdin, SV
有害突变的基因组发生率和影响分布是进化理论中的重要参数。最详细的信息来自 Mukai 和 Ohnishi 的工作，他们允许突变在黑腹果蝇第二染色体上积累，通过在雄性中保持杂合来避免选择和重组。经过研究平均后，在等效应模型 U-BM 下，每代每条染色体的非致命性活力突变的估计率为 0.12，表明基因组突变率很高。我们进行了类似于 Mukai 和 Ohnishi 的突变积累实验，不同之处在于维持了三个大的纯合对照群体。突变积累 27-33 代后，对 72 个非致死突变积累 (MA) 系和对照的卵到成虫的活力进行了测定。平均生存力的下降率明显低于 Mukai 观察到的，而线间方差的增加率明显较高，我们的 U-BM 估计值 0.02 远低于之前的估计值。我们的结果表明，可检测到降低生存能力的突变率可能不会比致死突变率（这些品系中的0.01）大很多，但结果也与包含许多影响很小的突变的模型一致。
The genomic rate and distribution of effects of deleterious mutations are important parameters in evolutionary theory. The most detailed information comes from the work of Mukai and Ohnishi, who allowed mutations to accumulate on Drosophila melanogaster second chromosomes, shielded from selection and recombination by being maintained heterozygous in males. Averaged over studies, the estimated rate of nonlethal viability mutations per second chromosome per generation under an equal-effects model, U-BM, was 0.12, suggesting a high genomic mutation rate. We have performed a mutation-accumulation experiment similar to those of Mukai and Ohnishi, except that three large homozygous control populations were maintained. Egg-to-adult viability of 72 nonlethal mutation-accumulation (MA) lines and the controls was assayed after 27-33 generations of mutation accumulation. The rate of decline in mean viability was significantly lower than observed by Mukai, and the rate of increase in among-line variance was significantly higher, Our U-BM estimate of 0.02 is much lower than the previous estimates. Our results suggest that the rate of mutations that detectably reduce viability may not be much greater than the lethal mutation rate (0.01 in these lines), but the results also are consistent with models that include many mutations with very small effects.