title: Genetic variation and demographic history of the Haplochromis laparogramma group of Lake Victoria-An analysis based on SINEs and mitochondrial DNA.
abstract: More than 500 endemic haplochromine cichlid species inhabit Lake Victoria. This striking species diversity is a classical example of recent explosive adaptive radiation thought to have happened within the last approximately 15,000 years. In this study, we examined the population structure and historical demography of 3 pelagic haplochromine cichlid species that resemble in morphology and have similar niche, Haplochromis (Yssichromis) laparogramma, Haplochromis (Y.) pyrrhocephalus, and Haplochromis (Y.) sp. "glaucocephalus". We investigated the sequences of the mitochondrial DNA control region and the insertion patterns of short interspersed elements (SINEs) of 759 individuals. We show that sympatric forms are genetically differentiated in 4 of 6 cases, but we also found apparent weakening of the genetic differentiation in areas with turbid water. We estimated the timings of population expansion and species divergence to coincide with the refilling of the lake at the Pleistocene/Holocene boundary. We also found that estimates can be altered significantly by the choice of the shape of the molecular clock. If we employ the nonlinear clock model of evolutionary rates in which the rates are higher towards the recent, the population expansion was dated at around the event of desiccation of the lake ca. 17,000 YBP. Thus, we succeeded in clarifying the species and population structure of closely related Lake Victoria cichlids and in showing the importance of applying appropriate clock calibrations in elucidating recent evolutionary events.
authors.affiliation: Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, Midori-ku, Yokohama 226-8501, Japan.
authors.forename: Semvua I
authors.initials: SI
authors.lastname: Mzighani
authors.forename: Masato
authors.initials: M
authors.lastname: Nikaido
authors.forename: Miyuki
authors.initials: M
authors.lastname: Takeda
authors.forename: Ole
authors.initials: O
authors.lastname: Seehausen
authors.forename: Yohana L
authors.initials: YL
authors.lastname: Budeba
authors.forename: Benjamin P
authors.initials: BP
authors.lastname: Ngatunga
authors.forename: Egid F B
authors.initials: EF
authors.lastname: Katunzi
authors.forename: Mitsuto
authors.initials: M
authors.lastname: Aibara
authors.forename: Shinji
authors.initials: S
authors.lastname: Mizoiri
authors.forename: Tetsu
authors.initials: T
authors.lastname: Sato
authors.forename: Hidenori
authors.initials: H
authors.lastname: Tachida
authors.forename: Norihiro
authors.initials: N
authors.lastname: Okada
mesh_terms: D000818:Animals; D023681:Cichlids / Q000235:genetics*; D004272:DNA, Mitochondrial / Q000235:genetics*; D003710:Demography; D005618:Fresh Water; D014644:Genetic Variation; D020086:Short Interspersed Nucleotide Elements / Q000235:genetics*
chemical_list: D004272:DNA, Mitochondrial