Levitan Don R, Terhorst Casey P, Fogarty Nicole D
Department of Biological Science, Florida State University, Tallahassee, Florida 32306-1100, USA.
Evolution. 2007 Aug;61(8):2007-14. doi: 10.1111/j.1558-5646.2007.00150.x.
Developmental failure caused by excess sperm (polyspermy) is thought to be an important mechanism driving the evolution of gamete-recognition proteins, reproductive isolation, and speciation in marine organisms. However, these theories assume that there is heritable variation in the susceptibility to polyspermy and that this variation is related to the overall affinity between sperm and eggs. These assumptions have not been critically examined. We investigated the relationship between ease of fertilization and susceptibility to polyspermy within and among three congeneric sea urchins. The results from laboratory studies indicate that, both within and among species, individuals and species that produce eggs capable of fertilization at relatively low sperm concentrations are more susceptible to polyspermy, whereas individuals and species producing eggs that require higher concentrations of sperm to be fertilized are more resistant to polyspermy. This relationship sets the stage for selection on gamete traits that depend on sperm availability and for sexual conflict that can influence the evolution of gamete-recognition proteins and eventually lead to reproductive isolation.
由过多精子导致的发育失败（多精入卵）被认为是推动海洋生物中配子识别蛋白进化、生殖隔离和物种形成的重要机制。然而，这些理论假设多精入卵的易感性存在可遗传变异，且这种变异与精子和卵子之间的总体亲和力有关。这些假设尚未得到严格检验。我们研究了三种同属海胆内部及之间受精难易程度与多精入卵易感性之间的关系。实验室研究结果表明，无论是在物种内部还是物种之间，能够在相对较低精子浓度下受精的个体和物种更容易发生多精入卵，而产生需要更高精子浓度才能受精的卵子的个体和物种对多精入卵更具抗性。这种关系为依赖精子可用性的配子性状选择以及可能影响配子识别蛋白进化并最终导致生殖隔离的性冲突奠定了基础。
