Klein Jan, Sato Akie, Nikolaidis Nikolas
Department of Biology, The Pennsylvania State University, University Park, PA 16801, USA.
Annu Rev Genet. 2007;41:281-304. doi: 10.1146/annurev.genet.41.110306.130137.
The acronym Mhc, major histocompatibility complex, is customarily not allied with topics in evolutionary biology. Here, however, we attempt to demonstrate that the Mhc has much to offer to this discipline and intimate that evolutionary biologists who ignore its contributions miss out on a chance of applying a new approach to vexing questions. One aspect of the Mhc in particular affords a fresh look at the population processes that transform one species into another: the trans-species polymorphism, the passage of allelic lineages from ancestral to descendant species. We provide examples of using the Mhc polymorphism in estimating the size of the founding population of new species, and of analyzing the long-term population demographies of phylogenetic lineages. We then extend the concept of trans-species polymorphism to other genes, even those not evolving under balancing selection, and argue that the phenomenon is widespread between closely related species. On the example of the cichlid fishes of Lake Victoria, we demonstrate how the concept changes the interpretation of this so-called "species flock." We contend that the conclusions reached regarding the cichlid fishes apply also to other examples of adaptive radiation, for example that of Darwin's finches, and so provide new insights into the nature of speciation in general.
首字母缩略词Mhc，即主要组织相容性复合体，通常与进化生物学的主题无关。然而，在此我们试图证明，Mhc能为这一学科提供很多东西，并暗示那些忽视其贡献的进化生物学家错失了应用新方法解决棘手问题的机会。Mhc的一个方面尤其能让我们重新审视将一个物种转变为另一个物种的种群过程：跨物种多态性，即等位基因谱系从祖先物种传递到后代物种。我们提供了利用Mhc多态性估计新物种奠基种群大小以及分析系统发育谱系长期种群统计学特征的实例。然后，我们将跨物种多态性的概念扩展到其他基因，甚至那些并非在平衡选择下进化的基因，并认为这种现象在密切相关的物种之间广泛存在。以维多利亚湖的丽鱼科鱼类为例，我们展示了这一概念如何改变对这个所谓“物种群”的解释。我们认为，关于丽鱼科鱼类得出的结论也适用于其他适应性辐射的例子，比如达尔文雀的例子，从而为一般物种形成的本质提供了新的见解。
