Filchak K E, Roethele J B, Feder J L
Department of Biological Sciences, Galvin Life Science Center, University of Notre Dame, Indiana 46556-0169, USA.
Nature. 2000 Oct 12;407(6805):739-42. doi: 10.1038/35037578.
In On the Origin of Species, Darwin proposed that natural selection had a fundamental role in speciation. But this view receded during the Modern Synthesis when allopatric (geographic) models of speciation were integrated with genetic studies of hybrid sterility and inviability. The sympatric hypothesis posits that ecological specialization after a host shift can result in speciation in the absence of complete geographic isolation. The apple maggot, Rhagoletis pomonella, is a model for sympatric speciation in progress. Hawthorn (Crataegus spp.) is the native host for R. pomonella in N. Americas. But in the mid-1800s, a new population formed on introduced, domesticated apple (Malus pumila). Recent studies have conferred 'host race' status on apple flies as a potentially incipient species, partially isolated from haw flies owing to host-related adaptation. However, the source of selection that differentiates apple and haw flies is unresolved. Here we document a gene-environment interaction (fitness trade-off) that is related to host phenology and that genetically differentiates the races.
在《物种起源》中，达尔文提出自然选择在物种形成中起着根本性作用。但在现代综合进化论时期，当异域（地理）物种形成模型与杂交不育和不存活的遗传学研究相结合时，这种观点就不再流行了。同域假说认为，宿主转移后的生态特化在没有完全地理隔离的情况下也能导致物种形成。苹果实蝇（Rhagoletis pomonella）是正在进行的同域物种形成的一个模型。山楂（Crataegus spp.）是北美苹果实蝇的原生宿主。但在19世纪中叶，在引入的驯化苹果（Malus pumila）上形成了一个新的种群。最近的研究赋予了苹果实蝇“宿主种族”的地位，作为一个潜在的初始物种，由于与宿主相关的适应性，它与山楂实蝇部分隔离。然而，区分苹果实蝇和山楂实蝇的选择来源尚未得到解决。在这里，我们记录了一种与宿主物候相关的基因-环境相互作用（适应性权衡）以及在基因上区分这两个种族的因素。
