Van Doorn G S, Luttikhuizen P C, Weissing F J
Department of Genetics, University of Groningen, PO Box 14, 9750 AA Haren, The Netherlands.
Proc Biol Sci. 2001 Oct 22;268(1481):2155-61. doi: 10.1098/rspb.2001.1780.
An increasing number of molecular studies are indicating that, in a wide variety of species, genes directly related to fertilization evolve at extraordinarily high rates. We try to gain insight into the dynamics of this rapid evolution and its underlying mechanisms by means of a simple theoretical model. In the model, sexual selection and sympatric speciation act together in order to drive rapid divergence of gamete recognition proteins. In this process, intraspecific competition for fertilizations enlarges male gamete protein variation by means of evolutionary branching, which initiates sympatric speciation. In addition, avoidance of competition for fertilizations between the incipient species drives the rapid evolution of gamete recognition proteins. This mechanism can account for both strong stabilizing selection on gamete recognition proteins within species and rapid divergence between species. Moreover, it can explain the empirical finding that the rate of divergence of fertilization genes is not constant, but highest between closely related species.
越来越多的分子研究表明，在各种各样的物种中，与受精直接相关的基因以极高的速率进化。我们试图通过一个简单的理论模型来深入了解这种快速进化的动态过程及其潜在机制。在该模型中，性选择和同域物种形成共同作用，以推动配子识别蛋白的快速分化。在这个过程中，种内受精竞争通过进化分支扩大了雄配子蛋白的变异，从而引发同域物种形成。此外，避免初始物种之间的受精竞争推动了配子识别蛋白的快速进化。这种机制既可以解释物种内配子识别蛋白上强大的稳定选择，也可以解释物种间的快速分化。而且，它可以解释这样一个实证发现，即受精基因的分化速率并非恒定不变，而是在亲缘关系较近的物种之间最高。
