Department of Biochemistry, University of Geneva, Geneva, Switzerland.
Centre for Mathematics and Physics in the Life Sciences and Experimental Biology (CoMPLEX), University College London, London, United Kingdom.
Elife. 2019 Aug 29;8:e48239. doi: 10.7554/eLife.48239.
The two partners required for sexual reproduction are rarely the same. This pattern extends to species which lack sexual dimorphism yet possess self-incompatible gametes determined at mating-type regions of suppressed recombination, likely precursors of sex chromosomes. Here we investigate the role of cellular signaling in the evolution of mating-types. We develop a model of ligand-receptor dynamics, and identify factors that determine the capacity of cells to send and receive signals. The model specifies conditions favoring the evolution of gametes producing ligand and receptor asymmetrically and shows how these are affected by recombination. When the recombination rate evolves, the conditions favoring asymmetric signaling also favor tight linkage of ligand and receptor loci in distinct linkage groups. These results suggest that selection for asymmetric gamete signaling could be the first step in the evolution of non-recombinant mating-type loci, paving the road for the evolution of anisogamy and sexes.
进行有性生殖所需的两个配偶通常不相同。这种模式延伸到了那些缺乏性二态性但拥有自不亲和配子的物种，这些物种的自不亲和配子在交配型区域受到抑制重组的决定，可能是性染色体的前身。在这里，我们研究了细胞信号在交配型进化中的作用。我们开发了一个配体-受体动力学模型，并确定了决定细胞发送和接收信号能力的因素。该模型指定了有利于配子产生不对称配体和受体的条件，并展示了这些条件如何受到重组的影响。当重组率进化时，有利于不对称信号传递的条件也有利于在不同连锁群中紧密连锁的配体和受体基因座。这些结果表明，对不对称配子信号传递的选择可能是不重组交配型基因座进化的第一步，为非重组交配型基因座的进化铺平了道路，为雌雄异体和性别的进化铺平了道路。
