A new theory for the evolution of polyandry as a means of inbreeding avoidance
A new theory for the evolution of polyandry as a means of inbreeding avoidance
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DOI：
10.1098/rspb.2007.0926
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发表时间：
2007-11-22
影响因子：
4.7
通讯作者：
Tregenza, Tom
中科院分区：
文献类型：
--
作者：
Cornell, Stephen J.;Tregenza, Tom
我们提出了一种新的理论，由遗传利益驱动的一夫多妻制的进化对后代进行杂交的雌性。在以新栖息地频繁殖民为特征的物种中，近亲交配在殖民的早期阶段可能是常见的，但随着新的殖民者的到来，遗传多样性可能会增加。我们表明，近亲繁殖抑制水平与主要近亲繁殖群体中发现的水平相似，一夫多妻的雌性后代可以受益，因为她的后代之间的交配主要是在同父异母的兄弟姐妹之间，而不是全同胞兄弟姐妹之间。我们使用显性遗传模型研究了多性生殖表型的入侵，在这些模型中，近亲繁殖的成本本身受到选择的影响。与其他近亲交配模型一样，我们发现潜在的高水平近亲交配往往会清除有害的隐性等位基因，因此不太可能保持足够的近亲交配抑制来支持一夫多妻制。然而，如果近亲交配的成本是由于过度显性，那么生物上现实水平的近亲交配抑制会带来足够大的遗传利益，足以支持一夫多妻制，前提是它的成本不是太高。一夫多妻制作为减少孙辈近亲繁殖的一种机制的潜在意义将取决于自然近亲繁殖种群近亲繁殖衰退的遗传基础。
We propose a novel theory for the evolution of polyandry driven by genetic benefits to females whose offspring interbreed. In species with an ecology characterized by frequent colonization of new habitat patches, consanguineous matings may be common during the early stages of colonization, but genetic diversity may grow as new colonizers arrive. We show that with levels of inbreeding depression similar to those found in predominantly inbreeding populations, a polyandrous female can benefit her descendants since matings among her brood are mainly between half siblings rather than full siblings. We examine the invasion by a polyandrous phenotype using explicit genetic models in which costs of inbreeding are themselves subject to selection. In common with other models of inbreeding, we find that underlying high levels of inbreeding tend to purge deleterious recessive alleles, and hence these are unlikely to maintain sufficient inbreeding depression to favour polyandry. However, if costs of inbreeding are due to overdominance, biologically realistic levels of inbreeding depression result in genetic benefits large enough to favour polyandry provided it is not too costly. The potential significance of polyandry as a mechanism to reduce inbreeding in grandchildren will depend upon the genetic basis of inbreeding depression in natural, inbreeding populations.