Theoretical Biology Group, Centre for Ecological and Evolutionary Studies, University of Groningen, Kerklaan 30, 9750 AA Haren, The Netherlands.
Evolution. 2011 Feb;65(2):554-63. doi: 10.1111/j.1558-5646.2010.01148.x. Epub 2010 Nov 3.
Different genetic systems can be both the cause and the consequence of genetic conflict over the transmission of genes, obscuring their evolutionary origin. For instance, with paternal genome elimination (PGE), found in some insects and mites, both sexes develop from fertilized eggs, but in males the paternally derived chromosomes are either lost (embryonic PGE) or deactivated (germline PGE) during embryogenesis and not transmitted to the next generation. Evolution of germline PGE requires two transitions: (1) elimination of the paternal genome during spermatogenesis; (2) deactivation of the paternal genome early in development. Hypotheses for the evolution of PGE have mainly focused on the first transition. However, maternal genes seem to be responsible for the deactivation and here we investigate if maternal suppression could have evolved in response to paternally expressed male suicide genes. We show that sibling competition can cause such genes to spread quickly and that inbreeding is necessary to prevent fixation of male suicide, and subsequent population extinction. Once male-suicide has evolved, maternally expressed suppressor genes can invade in the population. Our results highlight the rich opportunity for genetic conflict in asymmetric genetic systems and the counterintuitive phenotypes that can evolve as a result.
不同的遗传系统既可以是基因传递过程中遗传冲突的原因，也可以是其结果，从而使它们的进化起源变得模糊不清。例如，在某些昆虫和螨虫中发现的父本基因组消除（PGE）现象，雌雄两性都由受精卵发育而来，但在雄性中，父本来源的染色体在胚胎发生过程中要么丢失（胚胎 PGE），要么失活（生殖细胞系 PGE），不会传递给下一代。生殖细胞系 PGE 的进化需要两个转变：（1）在精子发生过程中消除父本基因组；（2）在早期发育过程中使父本基因组失活。关于 PGE 进化的假说主要集中在第一个转变上。然而，母系基因似乎对失活负责，在这里我们研究了母系抑制是否可能是为了应对父系表达的雄性自杀基因而进化的。我们表明，同胞竞争会导致这些基因迅速传播，并且近亲繁殖对于防止雄性自杀基因的固定和随后的种群灭绝是必要的。一旦雄性自杀基因进化，母系表达的抑制基因就可以在种群中入侵。我们的研究结果强调了在不对称遗传系统中遗传冲突的丰富机会，以及由此产生的反直觉表型。
