Evolution of intermediate selfing rates in plants: pollination ecology versus deleterious mutations
Evolution of intermediate selfing rates in plants: pollination ecology versus deleterious mutations
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DOI：
10.1023/a:1017039010191
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发表时间：
1998-03
期刊：
影响因子：
1.5
通讯作者：
M. Johnston
中科院分区：
文献类型：
--
作者：
M. Johnston
在表型模型中研究了自交结实率的进化稳定性，该模型将授粉生态学以及近交衰退和群体平均自交率的相关进化结合起来。近亲繁殖衰退被认为是由有害的部分隐性等位基因的持续突变引起的。包括几个突变率和显性水平。两个独立的生态案例进行了研究：自交率如何影响受精胚珠的比例（授粉保证，种子折扣）和自交率如何影响男性异交成功，通过花粉折扣。在两种情况下，即增加自交导致（1）受精胚珠比例下降或（2）花粉折扣增加，因此雄性异交成功率不成比例地下降时，进化稳定率总是零或中间值。完全自交是稳定的，当自交增加受精胚珠的比例为所有自交率。在自交率对受精胚珠的比例没有影响或花粉折扣不随自交而增加的情况下，稳定自交是零或一。较高的近交衰退倾向于降低最佳自交率，而较低的近交衰退（较高的显性系数和较低的突变率）更有利于稳定的中间自交率的存在。这样的方法，明确纳入自交，胚珠受精，雄性异交的相互依赖性，可能有助于解释动物授粉植物的中间自交率的持久性。
The evolutionarily stable rate of self-fertilzation is studied in phenotypic models that incorporate pollination ecology as well as the correlated evolution of inbreeding depression and the population mean selfing rate. Inbreeding depression is assumed to be caused by continual mutation to deleterious, partially recessive alleles. Several mutation rates and dominance levels are included. Two separate ecological cases are studied: how selfing rate affects proportion of ovules fertilized (pollination assurance, seed discounting) and how selfing rate affects male outcrossing success through pollen discounting. Evolutionarily stable rates are invariably zero or intermediate in two circumstances, namely when increased selfing causes (1) a decrease in the proportion of ovules fertilized or (2) an increase in pollen discounting and, therefore, a disproportionate decrease in male outcrossing success. Complete selfing is stable when selfing increases the proportion of ovules fertilized for all selfing rates. Stable selfing is zero or one in cases where the selfing rate has no effect on the proportion of ovules fertilized or when pollen discounting does not increase with selfing. Higher inbreeding depression tends to decrease the optimal selfing rate, and lower inbreeding depression (higher dominance coefficients and lower mutation rates) is more favorable to the existence of stable intermediate selfing rates. Approaches such as this that explicitly incorporate the interdependence of selfing, ovule fertilization, and male outcrossing may help explain the persistence of intermediate selfing rates in animal-pollinated plants.