Higher rates of sex evolve in spatially heterogeneous environments
Higher rates of sex evolve in spatially heterogeneous environments
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DOI：
10.1038/nature09449
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发表时间：
2010-11-04
期刊：
影响因子：
64.8
通讯作者：
Agrawal, Aneil F.
中科院分区：
文献类型：
--
作者：
Becks, Lutz;Agrawal, Aneil F.
有性生殖的进化和维持已经困扰了生物学家几十年（1,2）。虽然这个领域有丰富的假设（3-5），但实验证据很少。一些重要的实验已经证明了有性种群和无性种群在进化速度上的差异（6-8）；其他实验也记录了与基因混合有关的进化变化现象，如重组（9,10）和自交（11）。然而，种群内性别进化的直接实验极为罕见（参见参考文献12）。本文以萼花臂轮虫（Brachionus calyciflorus）为研究对象，对最近的理论（13-15）进行了验证，该理论预测在空间异质环境中有性进化的机会更多。在由高质量或低质量食物生境组成的同质环境中，或由两种生境混合组成的异质环境中，维持重复的轮虫实验种群。对于维持在任何一种同质环境中的种群，性的比率迅速向零进化。相比之下，在经历空间异质环境的种群中，性进化率更高。数据表明，在异质性下观察到的较高的性别水平不是由于性别成本较低或性别选择效率较低；相反，性别在异质环境中具有足够的优势，足以压倒其固有的成本(2)。与一些关于性进化的替代理论相反，没有证据表明遗传漂变在这些种群的性进化中起任何作用。
The evolution and maintenance of sexual reproduction has puzzled biologists for decades(1,2). Although this field is rich in hypotheses(3-5), experimental evidence is scarce. Some important experiments have demonstrated differences in evolutionary rates between sexual and asexual populations(6-8); other experiments have documented evolutionary changes in phenomena related to genetic mixing, such as recombination(9,10) and selfing(11). However, direct experiments of the evolution of sex within populations are extremely rare (but see ref. 12). Here we use the rotifer, Brachionus calyciflorus, which is capable of both sexual and asexual reproduction, to test recent theory(13-15) predicting that there is more opportunity for sex to evolve in spatially heterogeneous environments. Replicated experimental populations of rotifers were maintained in homogeneous environments, composed of either high-or low-quality food habitats, or in heterogeneous environments that consisted of a mix of the two habitats. For populations maintained in either type of homogeneous environment, the rate of sex evolves rapidly towards zero. In contrast, higher rates of sex evolve in populations experiencing spatially heterogeneous environments. The data indicate that the higher level of sex observed under heterogeneity is not due to sex being less costly or selection against sex being less efficient; rather sex is sufficiently advantageous in heterogeneous environments to overwhelm its inherent costs(2). Counter to some alternative theories(16,17) for the evolution of sex, there is no evidence that genetic drift plays any part in the evolution of sex in these populations.