Magalhaes I S, Mwaiko S, Schneider M V, Seehausen O
Aquatic Ecology and Evolution, Institute of Ecology & Evolution, University of Bern, Bern, Switzerland.
J Evol Biol. 2009 Feb;22(2):260-74. doi: 10.1111/j.1420-9101.2008.01637.x. Epub 2008 Nov 13.
Divergent selection acting on several different traits that cause multidimensional shifts are supposed to promote speciation, but the outcome of this process is highly dependent on the balance between the strength of selection vs. gene flow. Here, we studied a pair of sister species of Lake Victoria cichlids at a location where they hybridize and tested the hypothesis that divergent selection acting on several traits can maintain phenotypic differentiation despite gene flow. To explore the possible role of selection we tested for correlations between phenotypes and environment and compared phenotypic divergence (P(ST)) with that based on neutral markers (F(ST)). We found indications for disruptive selection acting on male breeding colour and divergent selection acting on several morphological traits. By performing common garden experiments we also separated the environmental and heritable components of divergence and found evidence for phenotypic plasticity in some morphological traits contributing to species differences.
作用于导致多维变化的几个不同性状的分歧选择被认为会促进物种形成，但这一过程的结果高度依赖于选择强度与基因流之间的平衡。在这里，我们在维多利亚湖丽鱼科鱼类的一对姐妹物种杂交的地点进行了研究，并检验了这样一个假设：尽管存在基因流，但作用于几个性状的分歧选择仍能维持表型分化。为了探究选择的可能作用，我们测试了表型与环境之间的相关性，并将表型分化（P(ST)）与基于中性标记的分化（F(ST)）进行了比较。我们发现了针对雄性繁殖颜色的间断选择以及针对几个形态性状的分歧选择的迹象。通过进行共同花园实验，我们还分离了分化的环境成分和遗传成分，并发现一些形态性状的表型可塑性有助于物种差异的证据。
