CLASSIFICATION OF HYPOTHESES ON THE ADVANTAGE OF AMPHIMIXIS
CLASSIFICATION OF HYPOTHESES ON THE ADVANTAGE OF AMPHIMIXIS
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DOI：
10.1093/oxfordjournals.jhered.a111358
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发表时间：
1993-09-01
影响因子：
3.1
通讯作者：
KONDRASHOV, AS
中科院分区：
文献类型：
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作者：
KONDRASHOV, AS
分类假说的优势，两性融合的无融合生殖。根据“直接利益”假说，两性融合是有利的，不管相互的基因交换，因为它直接增加后代的适应性，降低有害的突变率，或使选择更有效。相反，“变异和选择”假说将两性融合的优势归因于相互的基因交换，这种交换改变了后代的遗传变异性和对选择的反应。大多数这样的假说认为，双融合增加了选择的变异性和效率，但也有人声称双融合降低了选择的反应。变异和选择假说要求某些因素，随机漂移或上位选择，使不同等位基因的分布不独立，而另一个因素，基因型适合度的变化或有害突变，使过度代表的基因型非最佳。许多变异和选择假说，处理非结构化或空间结构化的人口，进行审查。其中两个似乎是最合理的：更好的反应的两性融合人口广泛波动的选择，和较低的突变负荷下的两性融合人口对有害突变的协同选择。在这两种情况下，两性融合的巨大优势需要相当严格的条件，这可以通过仔细的实验来证明。进一步了解两性融合的进化将主要依赖于这样的实验工作。
A classification of hypotheses on the advantage of amphimixis over apomixis is presented. According to ''Immediate Benefit'' hypotheses, amphimixis is advantageous regardless of reciprocal gene exchange, because either it directly increases fitness of the progeny, reduces the deleterious mutation rate, or makes selection more efficient. In contrast, ''Variation and Selection'' hypotheses attribute the advantage of amphimixis to the reciprocal gene exchange that alters genetic variability and response to selection among the progeny. Most such hypotheses assume that amphimixis increases variability and efficiency of selection, but some claim that amphimixis decreases response to selection. Variation and Selection hypotheses require that some factor, either random drift or epistatic selection, makes distributions of different alleles nonindependent, while another factor, either changes of the genotype fitnesses or deleterious mutations, makes overrepresented genotypes non-optimal. Numerous Variation and Selection hypotheses, dealing with either unstructured or spatially structured populations, are reviewed. Two of them seem most plausible: better responsiveness of the amphimictic population to widely fluctuating selection, and lower mutation load in the amphimictic population under synergistic selection against deleterious mutations. In both cases the large advantage of amphimixis requires rather stringent conditions, which could be falsified by careful experiment. Further progress in understanding the evolution of amphimixis will depend mostly on such experimental work.