Table of Contents
International Journal of Evolutionary Biology
Volume 2012 (2012), Article ID 865603, 9 pages
http://dx.doi.org/10.1155/2012/865603
Research Article

Extensive Introgression among Ancestral mtDNA Lineages: Phylogenetic Relationships of the Utaka within the Lake Malawi Cichlid Flock

1Interdisciplinary Research Centre, K. U. Leuven Campus Kortrijk, Etienne Sabbelaan 53, 8500 Kortrijk, Belgium
2KATHO, Wilgenstraat 32, 8800 Roeselare, Belgium
3Vertebrate Department, Royal Belgian Institute of Natural Sciences, Vautierstraat 29, 1000 Brussels, Belgium
4Evolutionary Ecology Group, University of Antwerp, Middelheimcampus G.V. 332, Groenenborgerlaan 171, 2020 Antwerp, Belgium
5Zoology Department, Royal Museum for Central Africa, Leuvensesteenweg 13, 3080 Tervuren, Belgium
6Laboratory of Biodiversity and Evolutionary Genomics, K. U. Leuven, Charles Deberiotstraat 32, 3000 Leuven, Belgium

Received 4 January 2012; Accepted 27 February 2012

Academic Editor: Stephan Koblmüller

Copyright © 2012 Dieter Anseeuw et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

We present a comprehensive phylogenetic analysis of the Utaka, an informal taxonomic group of cichlid species from Lake Malawi. We analyse both nuclear and mtDNA data from five Utaka species representing two (Copadichromis and Mchenga) of the three genera within Utaka. Within three of the five analysed species we find two very divergent mtDNA lineages. These lineages are widespread and occur sympatrically in conspecific individuals in different areas throughout the lake. In a broader taxonomic context including representatives of the main groups within the Lake Malawi cichlid fauna, we find that one of these lineages clusters within the non-Mbuna mtDNA clade, while the other forms a separate clade stemming from the base of the Malawian cichlid radiation. This second mtDNA lineage was only found in Utaka individuals, mostly within Copadichromis sp. “virginalis kajose” specimens. The nuclear genes analysed, on the other hand, did not show traces of divergence within each species. We suggest that the discrepancy between the mtDNA and the nuclear DNA signatures is best explained by a past hybridisation event by which the mtDNA of another species introgressed into the ancestral Copadichromis sp. “virginalis kajose” gene pool.