Identification of two genes causing reinforcement in the Texas wildflower Phlox drummondii
Identification of two genes causing reinforcement in the Texas wildflower Phlox drummondii
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DOI：
10.1038/nature09641
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发表时间：
2011-01-20
期刊：
影响因子：
64.8
通讯作者：
Rausher, Mark D.
中科院分区：
文献类型：
--
作者：
Hopkins, Robin;Rausher, Mark D.
物种的形成产生了生物多样性，并在防止种群间基因流动的特征进化时发生。在过去的15年里，识别这些特征背后基因的数量和分布，以及在少数情况下识别相关基因，极大地提高了我们对物种形成的理解(Noor和Feder（1)和Wolf等人(2)综述）。然而，这项工作几乎完全集中在限制种群之间基因流动的性状上，这些性状是地理上孤立的种群之间遗传分歧的副产品。相比之下，人们对与强化相关的基因特征知之甚少，强化是自然选择在物种形成过程中直接倾向于限制基因流动的过程。在这里，我们发现了两种基因的变化，这两种基因似乎导致了drummondii夹竹桃的颜色变化，之前的研究表明，这有助于强化。这两种变化都涉及花青素生物合成途径（ABP）基因的顺式调控突变。因为一种变化是隐性的，而另一种是显性的，杂交后代产生的中间颜色很少被传粉者访问，可能是不适应的。因此，选择增加合子前分离的遗传变化似乎也导致增加合子后分离。
Species formation generates biological diversity and occurs when traits evolve that prevent gene flow between populations. Discerning the number and distribution of genes underlying these traits and, in a few cases, identifying the genes involved, has greatly enhanced our understanding over the past 15 years of species formation (reviewed by Noor and Feder(1) and Wolf et al.(2)). However, this work has almost exclusively focused on traits that restrict gene flow between populations that have evolved as a by-product of genetic divergence between geographically isolated populations. By contrast, little is known about the characteristics of genes associated with reinforcement, the process by which natural selection directly favours restricted gene flow during the formation of species. Here we identify changes in two genes that appear to cause a flower colour change in Phlox drummondii, which previous work has shown contributes to reinforcement. Both changes involve cis-regulatory mutations to genes in the anthocyanin biosynthetic pathway (ABP). Because one change is recessive whereas the other is dominant, hybrid offspring produce an intermediate flower colour that is visited less by pollinators, and is presumably maladaptive. Thus genetic change selected to increase prezygotic isolation also appears to result in increased postzygotic isolation.