Evolution of accelerated senescence in laboratory populations of Drosophila.
Evolution of accelerated senescence in laboratory populations of Drosophila.
复制标题
果蝇实验室种群加速衰老的进化。
DOI：
10.1073/pnas.84.7.1974
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发表时间：
1987
影响因子：
11.1
通讯作者：
Mueller,LD
中科院分区：
文献类型：
--
作者：
Mueller,LD
生命史进化的生态理论预测，在幼年存活率相对于成年存活率较高且人口增长率较高的环境中，自然选择应该有利于单胎生命史。也就是说，生物体应该在成熟后的短时间内完成其全部繁殖工作。这一想法缺乏直接的实证验证。六个独立的黑腹果蝇种群在两种不同的环境（称为 r 和 K）中维持了 120 多代。在r环境中，种群规模较小，幼虫存活率和种群增长率较高，繁殖仅限于羽化后几天。在 K 环境中，种群规模较大，幼虫存活率较低，但成虫可以无限期繁殖。连续 4 周，每天测量不同环境中不同体型雌性的生育力。对于来自这两种环境的雌性来说，在成年后的第一周，生育力没有差异。然而，到了第四周，来自 r 环境的大型雌性的繁殖力比来自 K 环境的雌性低 47-83%。来自r环境的雌性所表现出的加速衰老似乎是由于有害等位基因的积累，其影响在生命后期才表达，这与衰老进化的突变积累假说是一致的。
Ecological theories of life history evolution predict that natural selection should favor semelparous life histories in environments where juvenile survival is high relative to adult survival and rates of population growth are high. That is, organisms should complete their entire reproductive effort in a short period of time following maturation. Direct empirical verification of this idea has been lacking. Six independent populations of Drosophila melanogaster were maintained in two different environments, called r and K, for more than 120 generations. In the r environment population size was small, larval survival and rates of population growth were high, and reproduction was limited to a few days after eclosion. In the K environment population size was large and larval survival low, but adults were allowed to reproduce indefinitely. The fecundity of females of different sizes from each environment was measured daily for 4 weeks. No differences in fecundity were seen during the first week of adult life for females from the two environments. By the fourth week, however, the fecundity of large females from the r environment was 47-83% less than that of females from the K environment. The accelerated senescence exhibited by females from the r environment appears to be due to the accumulation of deleterious alleles whose effects are expressed late in life, which is consistent with the mutation accumulation hypothesis for the evolution of senescence.