The Study of Gene Exchange During Recent Speciation Events among Cichlids of Lake Malawi

有超过一千种鱼类在家庭慈鲷科（慈鲷）在世界各地，但令人惊讶的是，大多数这种多样性发生在非洲大湖，马拉维（尼亚萨），坦噶尼喀，和维多利亚。 从进化的角度来看，这些湖泊的年龄并不算大，生物学家们对这些湖泊中存在的数百种独特的慈鲷物种如何迅速出现感到困惑。 传统的物种形成模型假设，独立的物种最初开始是不交换基因的孤立种群。 然而，一个重要的替代模型，可以适用于没有尖锐的障碍，迁移，是物种出现没有人口分离。 这种模式包括新形成物种之间的基因交换，以及自然选择导致的分歧。 这是一个有趣的模型，但很难测试。 在这个项目中，研究人员将通过应用一种新开发的遗传程序来检测马拉维湖几种慈鲷物种之间最近的基因交换来测试该模型。 马拉维湖的慈鲷已经成为许多研究物种形成的研究人员的模型系统。 然而，与其他新近形成的物种一样，这里的关键问题是，自然选择是否直接导致了分化，或者物种是否是作为完全分离的种群出现的，这些种群分别分化。 这个问题对于理解生物多样性是如何产生的至关重要。

There are over one thousand species of fish in the family Cichlidae (Cichlids) throughout the world, but surprisingly most of this diversity occurs in the great African lakes, Malawi (Nyasa), Tanganyika, and Victoria. These lakes are not of great age, in evolutionary terms, and biologists are puzzled over how the hundreds of unique Cichlid species, that exist in each of these lakes, could have arisen quickly. The traditional model of species formation assumes that separate species first begin as isolated populations that do not exchange genes. However, an important alternative model that could apply where there are not sharp barriers to migration, is that species arise without population separation. This model includes gene exchange between newly forming species, as well as natural selection acting to cause divergence. It is an interesting model, but difficult to test. In this project, researchers will test the model by applying a newly developed genetic procedure for detecting recent gene exchange between several Cichlid species from Lake Malawi. The Cichlids of Lake Malawi have become a model system for many researchers studying speciation. Yet the critical question here, as in other cases of recently formed species, is whether natural selection has caused the divergence directly, or whether species arise as completely separate populations that diverge separately. This question is fundamental to the understanding of how biological diversity arises.