DOES GENE FLOW CONSTRAIN ADAPTIVE DIVERGENCE OR VICE VERSA? A TEST USING ECOMORPHOLOGY AND SEXUAL ISOLATION IN TIMEMA CRISTINAE WALKING‐STICKS
DOES GENE FLOW CONSTRAIN ADAPTIVE DIVERGENCE OR VICE VERSA? A TEST USING ECOMORPHOLOGY AND SEXUAL ISOLATION IN TIMEMA CRISTINAE WALKING‐STICKS
复制标题
在 TIMEMA Cristinae 拐杖中使用生态学和性别隔离进行的测试是基因流限制适应性分化还是反之亦然？
DOI：
10.1111/j.0014-3820.2004.tb01577.x
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发表时间：
2004
期刊：
影响因子：
3.3
通讯作者：
Bernard J. Crespi
中科院分区：
文献类型：
--
作者：
Patrik Nosil;Bernard J. Crespi
种群分化往往反映了趋异的自然选择和生物基因流侵蚀选择效应的机会之间的平衡。然而，在生态物种形成过程中，性状分化导致生殖隔离，并成为基因流减少的原因，而不是结果。为了评估形态分化的原因和生殖后果，我们研究了17个种群的Timema cristinae手杖的形态分化和性隔离。个体适应使用Adenostoma作为宿主植物的群体往往表现出较小的整体尺寸，宽头，短腿相对于使用Ceonothus作为宿主的个体。然而，也有显着的变化，在宿主植物物种内的种群之间的形态。每个单一种群的平均性状值可以根据所使用的宿主植物和潜在的基因流来可靠地预测，这是使用替代宿主和基因流的线粒体DNA估计值从相邻种群的大小推断的。在群体间交配试验中，形态学不影响交配概率。因此，形态分歧是促进减少基因流，但不会导致减少基因流通过进化的性隔离。结合饲养数据表明大小和形状有部分遗传基础，宿主相关形式平行起源的证据，以及功能形态学的推论，这些结果表明T. cristinae反映了宿主特异性自然选择和基因流动之间的平衡。我们的研究结果说明了交配偏好的数据如何有助于确定性状分歧和基因流水平之间的因果关系。
Abstract Population differentiation often reflects a balance between divergent natural selection and the opportunity for homogenizing gene flow to erode the effects of selection. However, during ecological speciation, trait divergence results in reproductive isolation and becomes a cause, rather than a consequence, of reductions in gene flow. To assess both the causes and the reproductive consequences of morphological differentiation, we examined morphological divergence and sexual isolation among 17 populations of Timema cristinae walking‐sticks. Individuals from populations adapted to using Adenostoma as a host plant tended to exhibit smaller overall body size, wide heads, and short legs relative to individuals using Ceonothus as a host. However, there was also significant variation in morphology among populations within host‐plant species. Mean trait values for each single population could be reliably predicted based upon host‐plant used and the potential for homogenizing gene flow, inferred from the size of the neighboring population using the alternate host and mitochondrial DNA estimates of gene flow. Morphology did not influence the probability of copulation in between‐population mating trials. Thus, morphological divergence is facilitated by reductions in gene flow, but does not cause reductions in gene flow via the evolution of sexual isolation. Combined with rearing data indicating that size and shape have a partial genetic basis, evidence for parallel origins of the host‐associated forms, and inferences from functional morphology, these results indicate that morphological divergence in T. cristinae reflects a balance between the effects of host‐specific natural selection and gene flow. Our findings illustrate how data on mating preferences can help determine the causal associations between trait divergence and levels of gene flow.