Unckless R L, Orr H A
Department of Biology, University of Rochester, Rochester, NY 14627, USA.
Heredity (Edinb). 2009 Mar;102(3):214-7. doi: 10.1038/hdy.2008.129. Epub 2009 Jan 14.
Natural selection might drive the evolution of postzygotic reproductive isolation even when allopatric populations adapt to identical environments, an idea first suggested by Muller (1942). Here, we analyze this scenario mathematically, focusing on the evolution of a Dobzhansky-Muller incompatibility (DMI) between populations. Our results identify a potential problem with Muller's scenario: adaptation to identical environments can often involve substitution of the same alleles, precluding formation of a hybrid incompatibility. We show that the probability of evolving a DMI falls as selection coefficients among beneficial alleles become less similar. The reason is that if one locus is under much stronger selection than the other, that locus is much more likely to experience a substitution first in both populations. This precludes the development of a DMI, which requires different substitutions in the two populations.
即使异域种群适应相同的环境，自然选择也可能推动合子后生殖隔离的进化，这一观点最早由穆勒（1942年）提出。在此，我们从数学角度分析这种情况，重点关注种群间多布赞斯基 - 穆勒不相容性（DMI）的进化。我们的结果揭示了穆勒设想存在的一个潜在问题：适应相同环境通常涉及相同等位基因的替换，从而排除了杂种不相容性的形成。我们表明，随着有益等位基因间的选择系数变得不那么相似，进化出DMI的概率会下降。原因是，如果一个位点的选择压力比另一个位点强得多，那么该位点在两个种群中都更有可能首先发生替换。这就排除了DMI的发展，因为DMI需要两个种群发生不同的替换。
