Population structure in two sympatric species of the Lake Tanganyika cichlid tribe Eretmodini: evidence for introgression

• DOI: 10.1046/j.1365-294x.2001.01259.x
• Publication Date: 2003-03-12T10:42:18Z
• Authors: Lukas Rüber; Axel Meyer; Christian Sturmbauer; Erik Verheyen
• Keywords: Introgression; Cichlid; mtDNA control region; Genetic divergence

Patterns of genetic differentiation were analysed and compared in two sympatric species the endemic Lake Tanganyika cichlid tribe Eretmodini by means mitochondrial DNA (mtDNA) sequences control region six microsatellite loci. The sample area covers a total 138 km mostly uninterrupted rocky shoreline Democratic Republic Congo includes entire distribution range Tanganicodus cf. irsacae that stretches over distance 35 km. Both markers detected significant within between species. T. contained lower overall variation than Eretmoduscyanostictus, possibly due to its more restricted smaller effective population sizes. Complete fixation mtDNA haplotypes was observed Eretmodus at localities, while other localities some individuals possessed haplotypes. Taking into account relatively large average sequence divergence 6.2% species, as well geographical lake, pattern is likely be consequence asymmetric introgression shared ancestral polymorphism. As there populations, events introgressions may have happened after secondary contact, but our data provide no evidence for ongoing gene flow suggest both are reproductively isolated present time.