Genetic Basis of Adaptive Morphological Radiation in Lake Malawi Cichlid Fishes

在东非的湖泊中，慈鲷鱼经历了一场非同寻常的适应性辐射，使其成为一千多种鱼类。它们成功的关键是它们的口颌的多样化，这使它们能够采用特殊的进食方式。人们对这些颌骨形态差异的遗传基础知之甚少。有多少基因控制着口腔颌形的差异？相同的基因与不同的头部结构有关吗？什么样的基因控制着下巴的形状？控制颌骨形态差异的遗传因素将在两个马拉维湖物种之间的杂交杂交中进行研究，这些物种具有完全不同的颌骨。将对F2动物大家族的形态进行表征，并对分布在基因组中的100个DNA标记进行基因分型。通过分析特定的标记等位基因对颌骨形状的影响，就有可能估计影响形态各个方面的基因的数量、作用方式（加性遗传或显性遗传）和染色体位置。这些知识将有助于理解形态多样化及其在这些显著的脊椎动物辐射中的作用。此外，该模型系统中与颌骨发育有关的许多基因很可能与包括人类在内的其他脊椎动物的颌骨发育有关。

Kocher 9905127 Cichlid fishes have undergone an extraordinary adaptive radiation into more than one thousand species in the lakes of East Africa. Key to their success has been the diversification of their oral jaws, which allows them to adopt specialized modes of feeding. Little is known about the genetic basis for these differences in jaw morphology. How many genes control the differences in oral jaw shape? Are the same genes involved in different structures of the head? What kinds of genes control the shape of the jaw? The genetic factors controlling differences in jaw morphology will be studied in a hybrid cross between two Lake Malawi species with radically different jaws. The morphology of a large family of F2 animals will be characterized and each animal genotyped for 100 DNA markers distributed across the genome. By analyzing the effects of particular marker alleles on jaw shape it will be possible to estimate the number, mode of action (additive or dominant inheritance) and chromosomal position of genes contributing to each aspect of morphology. This knowledge will contribute to the understanding of morphological diversification and its role in these remarkable vertebrate radiations. In addition, many of the genes involved in jaw development in this model system are likely to be involved in the development of jaws in other vertebrates, including humans.