Department of Ecology and Evolutionary Biology, University of California, Santa Cruz, Santa Cruz, CA, 95060, USA.
Mol Ecol. 2016 Nov;25(22):5608-5610. doi: 10.1111/mec.13873.
Coevolution is one of the major processes organizing the earth's biodiversity, but it remains unclear when and how it may generate species diversity. The study by Parchman et al. () in this issue of Molecular Ecology provides the clearest evidence to date that divergent local adaptation in a coevolving interaction may lead to speciation on one side of an interaction but not necessarily on the other side. Red crossbills in North America have diversified into ecotypes that specialize on different conifer species, use different calls and vary in the extent to which they are nomadic or sedentary. This new study evaluated genomic divergence among nine crossbill ecotypes. The authors found low overall genomic divergence among many of the ecotypes, but the sedentary South Hills crossbills, which are specialized to eat the seeds of a unique population of lodgepole pines, showed substantial divergence from other crossbills at a small number of genomic regions. These results corroborate past studies showing local coadaptation of the morphological traits of South Hills crossbills and lodgepole pines, and premating isolation of the South Hills crossbills from other populations. Together, the past and new results suggest that local coevolution with lodgepole pines has led to reduced gene flow between South Hills crossbills and other crossbills.
协同进化是组织地球生物多样性的主要过程之一，但它何时以及如何产生物种多样性仍不清楚。Parchman 等人在本期《分子生态学》中进行的研究（）提供了迄今为止最明确的证据，表明协同进化相互作用中的分歧性局部适应可能导致一侧物种形成，但不一定导致另一侧物种形成。北美的红翅椋鸟已经分化成专门吃不同针叶树物种的生态型，使用不同的叫声，并且在迁徙或定居的程度上有所不同。这项新研究评估了 9 个交嘴雀生态型之间的基因组差异。研究人员发现，许多生态型之间的整体基因组差异很小，但专门吃一种独特的花旗松种群种子的久坐不动的南山交嘴雀与其他交嘴雀在少数基因组区域存在大量差异。这些结果与过去的研究相吻合，表明南山交嘴雀和花旗松的形态特征存在局部协同适应，以及南山交嘴雀与其他种群之间的交配前隔离。过去和新的研究结果表明，与花旗松的局部协同进化导致了南山交嘴雀和其他交嘴雀之间基因流动的减少。
