Understanding the process of speciation is a primary goal of evolutionary biology, yet the question of whether speciation can reach completion in the presence of gene flow remains controversial. For more than 50 years, the cichlids of Africa, and more recently those in South and Central America, have served as model systems for the study of speciation in nature. Cichlids are distinguished by their enormous species richness, their diversity of behavioural and trophic adaptations, and their rapid rate of divergence. In both Africa and South and Central America, the repeated interaction of geology, new founder events and adaptive evolution has created a series of natural experiments with speciation occurring both within and between waterbodies of differing ages. In the "From the Cover" paper in this issue of the Journal of Molecular Ecology, Raffini, Schneider, Franchini, Kautt and Meyer move beyond the question of which mechanisms drive speciation, and instead show that divergent morphologies and physiologies translate into adaptive traits. They investigate differences in physiology and gene expression profiles in a benthic/limnetic species pair of Midas cichlidsin a 24,000-year-old Nicaraguan crater lake. While recently diverged, these two species demonstrate significant ecological, but limited genetic differentiation. The authors find that the distinct morphotypes translate into relevant differences in swimming performance and metabolic rates that correspond to differential gene expression profiles. Hence, the authors take an integrative approach examining the impacts of morphological differences on performance and niche partitioning: an approach that can advance our understanding of the drivers of morphological and physiological divergence during speciation.

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快速生态专业化的生理学：看麦达斯慈鲷。

了解物种形成的过程是进化生物学的主要目标，但是在存在基因流的情况下物种形成是否可以完成的问题仍然存在争议。50多年来，非洲的丽鱼科动物，以及最近在南美和中美洲的丽鱼科动物，已成为研究自然物种形成的模型系统。丽鱼科鱼以其丰富的物种丰富度，行为和营养适应的多样性以及迅速的分化速度而著称。在非洲以及南美和中美洲，地质，新创建者事件和适应性进化的反复相互作用创造了一系列自然实验，在不同年龄的水体内部和之间发生了物种形成。在本期《分子生态学杂志》的“从封面开始”一文中，拉菲尼（Raffini），施耐德（Schneider），弗朗西尼（Franchini），考特（Kautt）和迈耶（Meyer）超越了哪种机制驱动物种形成的问题，而是表明不同的形态和生理转化为适应性状。他们调查了在具有24,000年历史的尼加拉瓜火山口湖的Midas丽鱼科鱼类的底栖/边缘物种对中生理和基因表达谱的差异。虽然最近发生分歧，但这两个物种显示出显着的生态学意义，但遗传分化有限。作者发现，不同的形态型转化为游泳能力和新陈代谢速率的相关差异，与差异基因表达谱相对应。因此，作者采用综合方法研究了形态差异对性能和生态位分配的影响：