Rapid radiation, ancient incomplete lineage sorting and ancient hybridization in the endemic Lake Tanganyika cichlid tribe Tropheini

Department of Zoology, Karl-Franzens-University Graz, Universitätsplatz 2, A-8010 Graz, Austria.
Molecular Phylogenetics and Evolution (Impact Factor: 3.92). 04/2010; 55(1):318-34. DOI: 10.1016/j.ympev.2009.09.032
Source: PubMed


The evolutionary history of the endemic Lake Tanganyika cichlid tribe Tropheini, the sister group of the species flocks of Lake Malawi and the Lake Victoria region, was reconstructed from 2009 bp DNA sequence of two mitochondrial genes (ND2 and control region) and from 1293 AFLP markers. A period of rapid cladogenesis at the onset of the diversification of the Tropheini produced a multitude of specialized, predominantly rock-dwelling aufwuchs-feeders that now dominate in Lake Tanganyika's shallow habitat. Nested within the stenotopic rock-dwellers is a monophyletic group of species, which also utilize more sediment-rich habitat. Most of the extant species date back to at least 0.7 million years ago. Several instances of disagreement between AFLP and mtDNA tree topology are attributed to ancient incomplete lineage sorting, introgression and hybridization. A large degree of correspondence between AFLP clustering and trophic types indicated fewer cases of parallel evolution of trophic ecomorphology than previously inferred from mitochondrial data.

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Available from: Stephan Koblmüller, Oct 07, 2015
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    • "However, in contrast to the closely related color morphs within T. moorii, which were investigated in the present study, T. polli and T. sp. " black " may already have been reproductively isolated at the time of coming into secondary contact, as their divergence predates major lake-level fluctuations which shaped the current distribution of littoral populations (Koblm€ uller et al. 2010). The space along which Tropheus populations can segregate by depth is defined by the range of algal growth and extends approximately 10–40 m in width, depending on the slope of the shore. "
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    ABSTRACT: Assortative mating promotes reproductive isolation and allows allopatric specia-tion processes to continue in secondary contact. As mating patterns are determined by mate preferences and intrasexual competition, we investigated male–male competition and behavioral isolation in simulated secondary contact among allopatric populations. Three allopatric color morphs of the cichlid fish Tropheus were tested against each other. Dyadic male–male contests revealed dominance of red males over bluish and yellow-blotch males. Reproductive isolation in the presence of male–male competition was assessed from genetic parent-age in experimental ponds and was highly asymmetric among pairs of color morphs. Red females mated only with red males, whereas the other females performed variable degrees of heteromorphic mating. Discrepancies between mating patterns in ponds and female preferences in a competition-free, two-way choice paradigm suggested that the dominance of red males interfered with positive assortative mating of females of the subordinate morphs and provoked asymmet-ric hybridization. Between the nonred morphs, a significant excess of negative assortative mating by yellow-blotch females with bluish males did not coincide with asymmetric dominance among males. Hence, both negative assortative mating preferences and interference of male–male competition with positive assorta-tive preferences forestall premating isolation, the latter especially in environments unsupportive of competition-driven spatial segregation.
    Ecology and Evolution 04/2015; DOI:10.1002/ece3.1372 · 2.32 Impact Factor
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    • "We therefore propose the use of distribution patterns of gill parasites of the genus Cichlidogyrus to support the (sub-)generic classification of the Petrochromis-Interochromis complex . A similar approach was followed in the 'sediment dwelling' Tropheini (sensu Koblmüller et al. 2010), where the distribution patterns of Cichlidogyrus species and morphotypes provided an extra line of evidence used to re-define the genera Simochromis and Pseudosimochromis (Van Steenberge, 2014). "
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    ABSTRACT: The faunal diversity of Lake Tanganyika, with its fish species flocks and its importance as a cradle and reservoir of ancient fish lineages seeding other radiations, has generated a considerable scientific interest in the fields of evolution and biodiversity. The Tropheini, an endemic Tanganyikan cichlid tribe, fills a peculiar phylogenetic position, being closely related to the haplochromine radiations of Lakes Malawi and Victoria. Several problems remain regarding their genus-level classification. For example, the monotypic genus Interochromis is phylogenetically nested within Petrochromis; its only representative, I. loocki, has often been reclassified. As monogenean flatworms are useful markers for fish phylogeny and taxonomy, the monogenean fauna of Interochromis loocki was examined and compared to that of other tropheine cichlids. Three new monogenean species belonging to Cichlidogyrus are described from Interochromis loocki: Cichlidogyrus buescheri Pariselle and Vanhove, sp. nov., Cichlidogyrus schreyenbrichardorum Pariselle and Vanhove, sp. nov. and Cichlidogyrus vealli Pariselle and Vanhove, sp. nov. Their haptoral anchors remind more of congeners infecting species of Petrochromis than of all Cichli­dogyrus spp. hitherto described from other tropheine cichlids. Attachment organ morphology has been proven to mirror the phylogenetic affinities of Cichlidogyrus lineages. Therefore the monogenean parasite fauna of I. loocki reflects this host’s position within Petrochromis. Moreover, I. loocki differs in habitat choice from Petrochromis spp. This study hence confirms that host range and host-specificity in Cichlidogyrus spp. parasitizing tropheines is determined by the host’s phylogenetic position, rather than by a shared ecological niche.
    Contributions to zoology Bijdragen tot de dierkunde 01/2015; 84(1):25-38. · 1.66 Impact Factor
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    • "Our STRUCTURE analysis demonstrates that there are many markers shared throughout the range from east Texas to north Florida of the two proposed populations, likely indicating high levels of gene flow, but it is not possible to rule out incomplete lineage sorting (Fontenot et al., 2011). Incomplete lineage sorting is unlikely because the large number of randomly distributed markers throughout the genome effectively neutralize differential lineage sorting (Avise, 2004; Koblmuller et al., 2010). The Mantel test showed a significant, positive correlation between geographic and genetic distance. "
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    ABSTRACT: The Cottonmouth, Agkistrodon piscivorus, is a semi-aquatic pitviper that occupies the southeastern U.S. west into Texas. Several previous studies have investigated the biogeographic history of A. piscivorus. It has been hypothesized that A. piscivorus was split into two separate populations during the last glacial maximum and climate change has impacted its distribution. Additionally, a geographically isolated population of A. piscivorus occurs at the western limit of the species’ range in the Concho Valley of Texas. To investigate biogeography and population structure within A. piscivorus in Texas and throughout its range, we utilized amplified fragment length polymorphism (AFLP) and sequence data from cytochrome b (cyt-b). The AFLP data indicate a lack of gene flow between the population of A. piscivorus in the Concho Valley and other nearby populations. However, based on cyt-b, there is no genetic differentiation. The AFLP data for the entire species show a signature of two historic populations that have recently come into secondary contact. Finding two historic populations is consistent with previously published data based on mitochondrial DNA analyses; however, due to the rapid evolution rate of AFLP data, we were able to detect a high level of gene flow between these populations. We conclude that it is possible Texas and Florida served as refugia for A. piscivorus during the last glacial maximum, and, as the glaciers receded, the two populations expanded, coming into secondary contact. The subsequent gene flow has resulted in shared loci across the two populations. The difference between the conclusions drawn between our two markers and previous research is due to the different time scales that AFLP and cyt-b markers measure. The AFLP data provided a contemporary marker and cyt-b indicated historic separation.
    Copeia 11/2014; 2014(4):639-649. DOI:10.1643/CG-13-123 · 1.03 Impact Factor
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