Hurst L D, Atlan A, Bengtsson B O
Department of Genetics, Cambridge University, United Kingdom.
Q Rev Biol. 1996 Sep;71(3):317-64. doi: 10.1086/419442.
Self-promoting elements (also called ultraselfish genes, selfish genes, or selfish genetic elements) are vertically transmitted genetic entities that manipulate their "host" so as to promote their own spread, usually at a cost to other genes within the genome. Examples of such elements include meiotic drive genes and cytoplasmic sex ratio distorters. The spread of a self-promoting element creates the context for the spread of a suppressor acting within the same genome. We may thus say that a genetic conflict exists between different components of the same genome. Here we investigate the properties of such conflicts. First we consider the potential diversity of genomic conflicts and show that every genetic system has potential conflicts. This is followed by analysis of the logic of conflicts. Just as Evolutionarily Stable Strategy (ESS) terminology provides a short cut for discussion of much in behavioral ecology, so the language of modifier analysis provides a useful terminology on which to base discussions of conflicts. After defining genetic conflict, we provide a general analysis of the conflicting parties, and note a distinction between competing and conflicting genes. We then provide a taxonomy of possible short- and long-term outcomes of conflicts, noting that potential conflict in an unconstrained system can never be removed, and that the course of evolution owing to conflict is often unpredictable. The latter is most particularly true for strong conflicts in which suppressors may take surprising forms. The possibility of extended conflicts in the form of "arms races" between element and suppressor is illustrated. The peculiar redundancy of these systems is one possible trace of conflict, and others are discussed. That homologous conflicts may find highly different expression is discussed by referring to the mechanistic differences that are thought to underlie the action of the two best-described meiotic drive genes, and by the multiplicity of forms of cytoplasmic sex ratio distorters. The theoretical analysis establishes a logical basis for thinking about conflicts, but fails to establish the importance of conflict in evolution. We illustrate this contentious issue through consideration of some phenomena for whose evolution conflict has been proposed as an important force: the evolution of sex, sex determination, species, recombination, and uniparental inheritance of cytoplasmic genes. In general, it is proposed that conflict may be a central force in the evolution of genetic systems. We conclude that an analysis of conflict and its general importance in evolution is greatly aided by application of the concept of genetic power. We consider the possible components of genetic power and ask whether and how power evolves.
自我促进元件（也称为超自私基因、自私基因或自私遗传元件）是垂直传递的遗传实体，它们操纵其“宿主”以促进自身传播，通常会以基因组内其他基因的利益为代价。此类元件的例子包括减数分裂驱动基因和细胞质性别比例畸变因子。自我促进元件的传播为同一基因组内起作用的抑制因子的传播创造了条件。因此，我们可以说同一基因组的不同组成部分之间存在遗传冲突。在此，我们研究此类冲突的特性。首先，我们考虑基因组冲突的潜在多样性，并表明每个遗传系统都存在潜在冲突。接下来是对冲突逻辑的分析。正如进化稳定策略（ESS）术语为行为生态学中的许多讨论提供了捷径一样，修饰分析的语言为基于冲突讨论提供了有用的术语。在定义遗传冲突之后，我们对冲突各方进行了一般性分析，并指出了竞争基因和冲突基因之间的区别。然后，我们对冲突可能的短期和长期结果进行了分类，指出在无约束系统中潜在冲突永远无法消除，并且由于冲突导致的进化过程往往是不可预测的。对于抑制因子可能采取惊人形式的强烈冲突而言，情况尤其如此。文中说明了元件与抑制因子之间以“军备竞赛”形式出现的长期冲突的可能性。这些系统特有的冗余性是冲突的一种可能痕迹，文中还讨论了其他痕迹。通过参考被认为是两个描述最详尽的减数分裂驱动基因作用基础的机制差异，以及细胞质性别比例畸变因子形式的多样性，讨论了同源冲突可能表现出高度不同的情况。理论分析为思考冲突建立了逻辑基础，但未能确立冲突在进化中的重要性。我们通过考虑一些其进化过程中冲突被认为是重要力量的现象来说明这个有争议的问题：性别的进化、性别决定、物种、重组以及细胞质基因的单亲遗传。总体而言，有人提出冲突可能是遗传系统进化的核心力量。我们得出结论，应用遗传力的概念极大地有助于对冲突及其在进化中的总体重要性进行分析。我们考虑了遗传力可能的组成部分，并询问力量是否以及如何进化。
