The purpose of this study was to estimate the genetic distance, diversity and relationship of two large groups of Malawian cichlid, ‘mbuna’ living in rocky area and feeding on algae, and ‘non-mbuna’ in sandy area feeding on various items. A total of 78 species from 42 genera was determined for the DNA sequence of the mitochondrial control region. In a genetic tree, constructed with Kimura-2 parameter as a distance by NJ method, mbuna created only one group whereas non-mbuna created four groups by a single or multiple genera. Some genera, such as Campsochromis and Labeotropheus with no genetic diversity within genus constructed a small congeneric clade, suggesting genetic homogeneity. In contrast, some genera, such as Otopharynx and Placidochromis with a high genetic diversity, participated in multiple groups including mbuna and non-mbuna, suggesting genetic heterogeneity. The largest Group A, exclusively composed by non-mbuna, showed an apparently high average genetic distance whereas Group D, in which all mbuna participated, showed an apparently low average genetic distance. It was suggested that non-mbuna have attained much higher diversification than mbuna. This different diversification may partly be attributable to sexual selection strongly exerted in rocky habitats in contrast to strong ecological selection in sandy area.

中文翻译：

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基于线粒体DNA序列的马拉维湖丽鱼科鱼类的遗传关系

这项研究的目的是估计两个大型马拉维丽鱼科鱼的遗传距离，多样性和亲缘关系，生活在多岩石地区并以藻类为食的“姆巴纳”，以及在沙质地区以各种食物为食的“非姆纳”。确定了来自42个属的总共78​​个物种的线粒体控制区的DNA序列。在通过NJ方法将木村2参数作为距离构建的遗传树中，mbuna仅创建一个组，而非mbuna通过单个或多个属创建四组。一些属，如Campsochromis和Labeotropheus与属内没有遗传多样性构成的小同类进化枝，这表明遗传同质性。相反，一些属，例如卵母和Pchromidochromis具有较高的遗传多样性，参加了多个小组，包括姆巴纳和非姆纳巴，这表明遗传异质性。最大的A组仅由非动物组成，其平均遗传距离明显较高，而所有动物都参与的D组的平均遗传距离较低。有人提出，非姆纳姆人的多元化程度要高于姆纳姆人。与沙质地区强大的生态选择相反，这种不同的多样化可能部分归因于在岩石栖息地中强烈施加的性选择。