THE EXPRESSION OF SELF-INCOMPATIBILITY IN ANGIOSPERMS IS BIMODAL
THE EXPRESSION OF SELF-INCOMPATIBILITY IN ANGIOSPERMS IS BIMODAL
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DOI：
10.1111/j.1558-5646.2011.01505.x
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发表时间：
2012-04-01
期刊：
影响因子：
3.3
通讯作者：
Igic, Boris
中科院分区：
文献类型：
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作者：
Raduski, Andrew R.;Haney, Elizabeth B.;Igic, Boris
几乎一半的被子植物都表现出自交不亲和性。其余物种中有很大一部分是自交亲和的，它们要么使用各种方法进行异交，要么在一定程度上进行自花受精。由于具有中等水平自交不亲和性的群体和个体的普遍存在，将自交不亲和性的表达归类为近似二元性状已经变得有争议。我们收集了一个广泛报道的指数（指数的自交不亲和性[ISI]），用于评估的强度和变化的自交不亲和性从1200多个被子植物类群。它的分布是双峰和正相关的异交率，虽然与自交亲和类群内的关系较弱。相当一部分物种具有中间平均值的ISI。它们的发生可能是由于分离短暂的自交不亲和突变，平均文物，实验偏差，除了经常调用的稳定选择作用于自交不亲和的表达。选择通常也可能通过增加谱系出生率和死亡率而有利于具有高ISI值的分类群，并且它可能抵消表达ISI的中间值和低值的分类群内的较低水平选择优势。这种零假设几乎被普遍忽视，尽管它可以充分解释观察到的交配和繁殖系统的分布。
Self-incompatibility is expressed by nearly one-half of all angiosperms. A large proportion of the remaining species are self-compatible, and they either outcross using various contrivances or self-fertilize to some extent. Because of the common occurrence of populations and individuals with intermediate levels of self-incompatibility, categorization of the expression of self-incompatibility as an approximately binary trait has become controversial. We collect a widely reported index (index of self-incompatibility [ISI]) used to asses the strength and variation of self-incompatibility from over 1200 angiosperm taxa. Its distribution is bimodal and positively associated with outcrossing rate, albeit with a weak relationship within self-compatible taxa. A substantial fraction of species has intermediate mean values of ISI. Their occurrence can be caused by segregating ephemeral self-compatible mutations, averaging artifacts, and experimental biases, in addition to the often invoked stabilizing selection acting on the expression of self-incompatibility. Selection may also generally favor taxa with high ISI values through increased lineage birth and death rates, and it may counter lower level selection advantages within taxa expressing intermediate and low values of ISI. Such a null hypothesis is nearly universally overlooked, despite the fact that it could adequately explain the observed distribution of mating and breeding systems.