Article

Origin and speciation of haplochromine fishes in East African crater lakes investigated by the analysis of their mtDNA, Mhc genes, and SINEs.

Max-Planck-Institut für Biologie, Abteilung Immungenetik, Tübingen, Germany.
Molecular Biology and Evolution (Impact Factor: 14.31). 10/2003; 20(9):1448-62. DOI: 10.1093/molbev/msg151
Source: PubMed

ABSTRACT The Western Branch of the East African Great Rift Valley is pocketed with craters of extinct or dormant volcanoes. Many of the craters are filled with water, and the lakes are inhabited by fishes. The objective of the present study was to determine the amount and nature of genetic variation in haplochromine fishes inhabiting two of these crater lakes, Lake Lutoto and Lake Nshere, and to use this information to infer the origin and history of the two populations. To this end, sequences of mitochondrial (mt) DNA control region, exon 2 of major histocompatibility complex (Mhc) class II B genes, and short interspersed elements (SINEs) were analyzed. The results indicate that the Lake Nshere and Lake Lutoto fishes originated from different but related large founding populations derived from the Kazinga Channel, which connects Lake Edward and Lake George. Some of the genetic polymorphism that existed in the ancestral populations was lost in the populations of the two lakes. The polymorphism that has been retained has persisted for some 50000 generations (years). During this time, new mutations arose and became fixed in each of the two populations in the mtDNA, giving rise to sets of diagnostic substitutions. Each population evolved in isolation after the colonization of the lakes less than 50000 years ago. There appears to be no population structure within the crater lake fishes, and their present effective population sizes are in the order of 104 to 105 individuals. Comparisons with the endemic haplochromine species of Lake Victoria reveal interesting parallels, as well as differences, which may help to understand the nature of the speciation process.

Full-text

Available from: Naoko Takezaki, Mar 13, 2014
0 Followers
 · 
63 Views
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Background Misidentifications between exploited species may lead to inaccuracies in population assessments, with potentially irreversible conservation ramifications if overexploitation of either species is occurring. A notable showcase is provided by the realization that the roundscale spearfish (Tetrapturus georgii), a recently validated species, has been historically misidentified as the morphologically very similar and severely overfished white marlin (Kajikia albida) (IUCN listing: Vulnerable). In effect, no information exists on the population status and evolutionary history of the enigmatic roundscale spearfish, a large, highly vagile and broadly distributed pelagic species. We provide the first population genetic evaluation of the roundscale spearfish, utilizing nuclear microsatellite and mitochondrial DNA sequence markers. Furthermore, we re-evaluated existing white marlin mitochondrial genetic data and present our findings in a comparative context to the roundscale spearfish.ResultsMicrosatellite and mitochondrial (control region) DNA markers provided mixed evidence for roundscale spearfish population differentiation between the western north and south Atlantic regions, depending on marker-statistical analysis combination used. Mitochondrial DNA analyses provided strong signals of historical population growth for both white marlin and roundscale spearfish, but higher genetic diversity and effective female population size (1.5-1.9X) for white marlin.Conclusions The equivocal indications of roundscale spearfish population structure, combined with a smaller effective female population size compared to the white marlin, already a species of concern, suggests that a species-specific and precautionary management strategy recognizing two management units is prudent for this newly validated billfish.
    BMC Genetics 12/2014; 15(1):141. DOI:10.1186/PREACCEPT-1524888150134369 · 2.36 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Background The enormous diversity found in East African cichlid fishes in terms of morphology, coloration, and behavior have made them a model for the study of speciation and adaptive evolution. In particular, haplochromine cichlids, by far the most species-rich lineage of cichlids, are a well-known textbook example for parallel evolution. Southwestern Uganda is an area of high tectonic activity, and is home to numerous crater lakes. Many Ugandan crater lakes were colonized, apparently independently, by a single lineage of haplochromine cichlids. Thereby, this system could be considered a natural experiment in which one can study the interaction between geographical isolation and natural selection promoting phenotypic diversification.ResultsWe sampled 13 crater lakes and six potentially-ancestral older lakes and, using both mitochondrial and microsatellite markers, discovered strong genetic and morphological differentiation whereby (a) geographically close lakes tend to be genetically more similar and (b) three different geographic areas seem to have been colonized by three independent waves of colonization from the same source population. Using a geometric morphometric approach, we found that body shape elongation (i.e. a limnetic morphology) evolved repeatedly from the ancestral deeper-bodied benthic morphology in the clear and deep crater lake habitats.ConclusionsA pattern of strong genetic and morphological differentiation was observed in the Ugandan crater lakes. Our data suggest that body shape changes have repeatedly evolved into a more limnetic-like form in several Ugandan crater lakes after independent waves of colonization from the same source population. The observed morphological changes in crater lake cichlids are likely to result from a common selective regime.
    BMC Evolutionary Biology 02/2015; 15(1):9. DOI:10.1186/s12862-015-0287-3 · 3.41 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: To investigate the extent of genetic differentiation among populations, genetic polymorphism in gizzard shad Konosirus punctatus, collected from wild populations of eight locations in Korea and four locations in Japan, was examined using mitochondrial DNA (mtDNA) control region. Two distinct mitochondrial lineages were detected: Lineage A was only distributed around Korean coastal waters and dominates the western and southwestern coast group of Korea. While Japanese groups of K. punctatus were exclusively assigned to lineage B. The co-occurrence of both lineages in southeast and east coasts of Korean coastal waters indicated that the current distribution pattern of gizzard shad populations was constructed by secondary contact.
    Ichthyological Research 12/2014; DOI:10.1007/s10228-014-0450-7 · 0.96 Impact Factor