School of Physics and Astronomy, University of Nottingham, University Park, Nottingham NG7 2RD, UK.
J Theor Biol. 2010 Sep 21;266(2):219-25. doi: 10.1016/j.jtbi.2010.06.025. Epub 2010 Jun 25.
Gynodioecy is a breeding system in plants where populations consist of hermaphrodites and females. The females result from a genetic mutation which impairs pollen production in hermaphrodite plants. Most previous models for the evolution of gynodioecy do not take into account any spatial detail, which might be expected to play an important role in populations with short range interactions caused by poor or no locomotion. In this article we present a generalised mean-field analysis (which ignores any spatial detail), together with stochastic spatial simulations, to investigate the spatial effect on the evolution of gynodioecy. We show that, in a population of hermaphrodites where male sterility is caused by a dominant allele in a nuclear gene, mean-field calculations greatly underestimate the reproductive advantage females require to become viable under spatial constraints. This suggests that gynodioecy is less likely to evolve in plants with more localised pollination and seed setting. This may have implications for the evolution of dioecy, a breeding system in plants where the population consists of males and females, as gynodioecy is thought to be a route to dioecy. Our results also demonstrate that a lower frequency of females should be expected for gynodioecious populations when interactions are local. This is relevant when comparing the results of breeding experiments with observations of female frequency in the wild.
雌雄异熟是植物的一种繁殖系统，其中种群由雌雄同体和雌性组成。雌性是由一种基因突变引起的，这种基因突变会损害雌雄同体植物的花粉产生。大多数先前关于雌雄异熟进化的模型都没有考虑到任何空间细节，而这些细节可能在由于运动能力差或没有运动能力而导致短程相互作用的种群中发挥重要作用。在本文中，我们提出了一种广义的平均场分析（忽略任何空间细节），以及随机空间模拟，以研究空间对雌雄异熟进化的影响。我们表明，在一个由核基因中的显性等位基因引起雄性不育的雌雄同体种群中，平均场计算大大低估了雌性在空间限制下变得可行所需的生殖优势。这表明，在具有更本地化授粉和种子设置的植物中，雌雄异熟不太可能进化。这可能对植物中由雄性和雌性组成的二倍体繁殖系统的进化产生影响，因为雌雄异熟被认为是二倍体的一种途径。我们的结果还表明，当相互作用是局部的时，应该预期雌雄异熟种群中的雌性频率较低。这与比较繁殖实验的结果和野外观察到的雌性频率有关。
