Age-specific properties of spontaneous mutations affecting mortality in Drosophila melanogaster.
Age-specific properties of spontaneous mutations affecting mortality in Drosophila melanogaster.
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发表时间：
1998
期刊：
影响因子：
3.3
通讯作者：
S. Pletcher;D. Houle;J. Curtsinger
中科院分区：
文献类型：
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作者：
S. Pletcher;D. Houle;J. Curtsinger
使用29个黑腹果蝇品系进行了自发突变对年龄特异性死亡率影响的分析，这些品系已经积累了19代的自发突变。使用品系间的差异来估计每周死亡率的突变方差和不同年龄的每周死亡率之间的协方差。在生命早期（约30日龄）的雄性和雌性动物中均观察到显著的突变变异。对于老年人的死亡率，突变方差与零没有显著差异。年龄之间的突变相关性分离1或2周，一般是积极的，但他们单调下降，增加分离，使突变对早期年龄死亡率的影响是不相关的，在以后的年龄。个别线的分析显示，在有限的年龄范围内的突变引起的死亡率变化的几个例子。在早期和中年发现了突变的显著年龄特异性效应，但令人惊讶的是，老年人的死亡率基本上不受累积过程的影响。我们的研究结果提供了强有力的证据，存在一类多基因突变，影响死亡率的年龄特异性的基础上。这里测量的突变效应的模式直接关系到最近发表的估计果蝇死亡率的常设遗传方差，他们支持突变积累作为一个可行的衰老进化机制。
An analysis of the effects of spontaneous mutations affecting age-specific mortality was conducted using 29 lines of Drosophila melanogaster that had accumulated spontaneous mutations for 19 generations. Divergence among the lines was used to estimate the mutational variance for weekly mortality rates and the covariance between weekly mortality rates at different ages. Significant mutational variance was observed in both males and females early in life (up to approximately 30 days of age). Mutational variance was not significantly different from zero for mortality rates at older ages. Mutational correlations between ages separated by 1 or 2 wk were generally positive, but they declined monotonically with increasing separation such that mutational effects on early-age mortality were uncorrelated with effects at later ages. Analyses of individual lines revealed several instances of mutation-induced changes in mortality over a limited range of ages. Significant age-specific effects of mutations were identified in early and middle ages, but surprisingly, mortality rates at older ages were essentially unaffected by the accumulation procedure. Our results provide strong evidence for the existence of a class of polygenic mutations that affect mortality rates on an age-specific basis. The patterns of mutational effects measured here relate directly to recently published estimates of standing genetic variance for mortality in Drosophila, and they support mutation accumulation as a viable mechanism for the evolution of senescence.