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Pinho C, Cardoso V, Hey J. A population genetic assessment of taxonomic species: The case of Lake Malawi cichlid fishes. Mol Ecol Resour 2019; 19:1164-1180. [PMID: 31012255 PMCID: PMC6764894 DOI: 10.1111/1755-0998.13027] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2019] [Revised: 03/20/2019] [Accepted: 04/10/2019] [Indexed: 02/05/2023]
Abstract
Organisms sampled for population‐level research are typically assigned to species by morphological criteria. However, if those criteria are limited to one sex or life stage, or the organisms come from a complex of closely related forms, the species assignments may misdirect analyses. The impact of such sampling can be assessed from the correspondence of genetic clusters, identified only from patterns of genetic variation, to the species identified using only phenotypic criteria. We undertook this protocol with the rock‐dwelling mbuna cichlids of Lake Malawi, for which species within genera are usually identified using adult male coloration patterns. Given high local endemism of male colour patterns, and considerable allele sharing among species, there persists considerable taxonomic uncertainty in these fishes. Over 700 individuals from a single transect were photographed, genotyped and separately assigned: (a) to morphospecies using photographs; and (b) to genetic clusters using five widely used methods. Overall, the correspondence between clustering methods was strong for larger clusters, but methods varied widely in estimated number of clusters. The correspondence between morphospecies and genetic clusters was also strong for larger clusters, as well as some smaller clusters for some methods. These analyses generally affirm (a) adult male‐limited sampling and (b) the taxonomic status of Lake Malawi mbuna, as the species in our study largely appear to be well‐demarcated genetic entities. More generally, our analyses highlight the challenges for clustering methods when the number of populations is unknown, especially in cases of highly uneven sample sizes.
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Affiliation(s)
- Catarina Pinho
- CIBIO/InBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, Universidade do Porto, Vairão, Portugal
| | - Vera Cardoso
- CIBIO/InBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, Universidade do Porto, Vairão, Portugal
| | - Jody Hey
- Rutgers, the State University of New Jersey, Piscataway, New Jersey.,CCGG, Center for Computational Genetics and Genomics, Department of Biology, Temple University, Philadelphia, Pennsylvania
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Rico C, Normandeau E, Dion-Côté AM, Rico MI, Côté G, Bernatchez L. Combining next-generation sequencing and online databases for microsatellite development in non-model organisms. Sci Rep 2013; 3:3376. [PMID: 24296905 PMCID: PMC3847856 DOI: 10.1038/srep03376] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2013] [Accepted: 10/30/2013] [Indexed: 12/02/2022] Open
Abstract
Next-generation sequencing (NGS) is revolutionising marker development and the rapidly increasing amount of transcriptomes published across a wide variety of taxa is providing valuable sequence databases for the identification of genetic markers without the need to generate new sequences. Microsatellites are still the most important source of polymorphic markers in ecology and evolution. Motivated by our long-term interest in the adaptive radiation of a non-model species complex of whitefishes (Coregonus spp.), in this study, we focus on microsatellite characterisation and multiplex optimisation using transcriptome sequences generated by Illumina® and Roche-454, as well as online databases of Expressed Sequence Tags (EST) for the study of whitefish evolution and demographic history. We identified and optimised 40 polymorphic loci in multiplex PCR reactions and validated the robustness of our analyses by testing several population genetics and phylogeographic predictions using 494 fish from five lakes and 2 distinct ecotypes.
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Affiliation(s)
- Ciro Rico
- 1] Estación Biológica de Doñana, Consejo Superior de Investigaciones Científicas (EBD, CSIC), C/Américo Vespucio s/n, 41092 Sevilla, Spain [2] School of Marine Studies, University of the South Pacific, Lower Laucala Campus, Suva, Fiji Islands [3] Institut de Biologie Intégrative et des Systèmes (IBIS), Département de Biologie, Université Laval, Pavillon Charles-Eugène-Marchand, Québec G1V 0A6, Canada
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Konijnendijk N, Joyce DA, Mrosso HDJ, Egas M, Seehausen O. Community Genetics Reveal Elevated Levels of Sympatric Gene Flow among Morphologically Similar but Not among Morphologically Dissimilar Species of Lake Victoria Cichlid Fish. INTERNATIONAL JOURNAL OF EVOLUTIONARY BIOLOGY 2011; 2011:616320. [PMID: 22164342 PMCID: PMC3227470 DOI: 10.4061/2011/616320] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/06/2011] [Revised: 05/18/2011] [Accepted: 07/11/2011] [Indexed: 11/20/2022]
Abstract
We examined genetic structure among five species of Lake Victoria haplochromine cichlids in four island communities, using a full factorial sampling design that compared genetic differentiation between pairs of species and populations of varying morphological similarity and geographical proximity. We found that allopatric conspecific populations were on average significantly more strongly differentiated than sympatric heterospecific populations of morphologically similar species. Allopatric heterospecific populations of morphologically dissimilar species were most differentiated. Our work demonstrates that phenotypic divergence can be maintained and perhaps even evolve in sympatry despite considerable gene flow between species. Conversely, phenotypic resemblance among conspecific populations can be maintained despite geographical isolation. Additionally we show that anthropogenically increased hybridization does not affect all sympatric species evenly but predominantly affects morphologically similar and closely related species. This has important implications for the evolution of reproductive isolation between species These findings are also consistent with the hypothesis of speciation reversal due to weakening of divergent selection and reproductive isolation as a consequence of habitat homogenization and offers an evolutionary mechanistic explanation for the observation that species poor assemblages in turbid areas of the lake are characterized by just one or two species in each of a few morphologically distinct genera.
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Affiliation(s)
- N Konijnendijk
- Institute of Ecology and Evolution, University of Bern, Baltzerstrasse 6, CH-3012 Bern, Switzerland
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4
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GENNER MARTINJ, KNIGHT MAIRIE, HAESLER MARCELP, TURNER GEORGEF. Establishment and expansion of Lake Malawi rock fish populations after a dramatic Late Pleistocene lake level rise. Mol Ecol 2010; 19:170-82. [DOI: 10.1111/j.1365-294x.2009.04434.x] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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ZIDANA HASTINGS, TURNER GEORGEF, van OOSTERHOUT COCK, HÄNFLING BERND. Elevated mtDNA diversity in introduced populations ofCynotilapia afra(Günther 1894) in Lake Malawi National Park is evidence for multiple source populations and hybridization. Mol Ecol 2009; 18:4380-9. [DOI: 10.1111/j.1365-294x.2009.04362.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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6
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Blais J, Plenderleith M, Rico C, Taylor MI, Seehausen O, van Oosterhout C, Turner GF. Assortative mating among Lake Malawi cichlid fish populations is not simply predictable from male nuptial colour. BMC Evol Biol 2009; 9:53. [PMID: 19265521 PMCID: PMC2667177 DOI: 10.1186/1471-2148-9-53] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2008] [Accepted: 03/05/2009] [Indexed: 12/03/2022] Open
Abstract
Background Research on the evolution of reproductive isolation in African cichlid fishes has largely focussed on the role of male colours and female mate choice. Here, we tested predictions from the hypothesis that allopatric divergence in male colour is associated with corresponding divergence in preference. Methods We studied four populations of the Lake Malawi Pseudotropheus zebra complex. We predicted that more distantly-related populations that independently evolved similar colours would interbreed freely while more closely-related populations with different colours mate assortatively. We used microsatellite genotypes or mesh false-floors to assign paternity. Fisher's exact tests as well as Binomial and Wilcoxon tests were used to detect if mating departed from random expectations. Results Surprisingly, laboratory mate choice experiments revealed significant assortative mating not only between population pairs with differently coloured males, but between population pairs with similarly-coloured males too. This suggested that assortative mating could be based on non-visual cues, so we further examined the sensory basis of assortative mating between two populations with different male colour. Conducting trials under monochromatic (orange) light, intended to mask the distinctive male dorsal fin hues (blue v orange) of these populations, did not significantly affect the assortative mating by female P. emmiltos observed under control conditions. By contrast, assortative mating broke down when direct contact between female and male was prevented. Conclusion We suggest that non-visual cues, such as olfactory signals, may play an important role in mate choice and behavioural isolation in these and perhaps other African cichlid fish. Future speciation models aimed at explaining African cichlid radiations may therefore consider incorporating such mating cues in mate choice scenarios.
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Affiliation(s)
- Jonatan Blais
- Department of Biological Sciences, University of Hull, Hull HU6 7RX, UK.
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7
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Wagner CE, McCune AR. Contrasting patterns of spatial genetic structure in sympatric rock-dwelling cichlid fishes. Evolution 2009; 63:1312-26. [PMID: 19154384 DOI: 10.1111/j.1558-5646.2009.00612.x] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The cichlid fish of Lake Tanganyika in Eastern Africa are a celebrated example of both ecological and species diversification. Because population subdivision is likely to play an important role in the speciation process, understanding how habitat features interact with species' demographic, behavioral and ecological attributes to influence gene flow and population divergence may help explain the causes of high species richness in this and other systems. Here, we test the roles of isolation-by-habitat and isolation-by-distance in generating fine-scale population genetic structure in three sympatric species of habitat-restricted cichlids in Lake Tanganyika. Using multilocus microsatellite genotypes, we contrast patterns of population differentiation in these habitat specialists along a mosaic coastline of both favorable and unfavorable habitat. Despite their close phylogenetic relationship and shared habitat affinity, these species show striking differences in their pattern of genetic subdivision within the same geographical region, suggesting substantially different patterns of gene flow. In particular, two trophically specialized species exhibit much more restricted gene flow over sandy habitat than a trophically opportunistic species. This result suggests that ecological and behavioral traits have a strong influence on the scale and degree of population subdivision, a finding that has potentially important implications for understanding differential propensities for diversification among lineages and phylogenetic patterns of diversity.
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Affiliation(s)
- Catherine E Wagner
- Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, New York 14853, USA.
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SALZBURGER WALTER. The interaction of sexually and naturally selected traits in the adaptive radiations of cichlid fishes. Mol Ecol 2009; 18:169-85. [DOI: 10.1111/j.1365-294x.2008.03981.x] [Citation(s) in RCA: 193] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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9
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Maeda K, Takeda M, Kamiya K, Aibara M, Mzighani SI, Nishida M, Mizoiri S, Sato T, Terai Y, Okada N, Tachida H. Population structure of two closely related pelagic cichlids in Lake Victoria, Haplochromis pyrrhocephalus and H. laparogramma. Gene 2008; 441:67-73. [PMID: 19084056 DOI: 10.1016/j.gene.2008.11.008] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2008] [Revised: 11/05/2008] [Accepted: 11/11/2008] [Indexed: 11/17/2022]
Abstract
Cichlid fishes in Lake Victoria show spectacular diversification that is thought to be recent. Therefore, by investigating those fishes, we may be able to elucidate recently completed or ongoing speciation processes. We studied the population structures of two closely related pelagic cichlid species, Haplochromis pyrrhocephalus and H. laparogramma, using a mitochondrial DNA locus and 12 nuclear microsatellite loci as putative neutral markers. Ten and two populations of H. pyrrhocephalus and H. laparogramma, respectively, were sampled from the southern part of Lake Victoria. We grouped those 12 populations into four mutually differentiated regional populations, one of which consisted of the two H. laparogramma populations. The levels of differentiation were substantial at the mitochondrial locus (F(ST) = 0.03-0.54), but very low at microsatellite loci (R(ST) = 0.008-0.116). The data from both types of loci indicated that the regional population of H. laparogramma was first separated from those of H. pyrrhocephalus if we set aside one erratic population of H. pyrrhocephalus. The data also suggested recent population expansions of the two species, the time scales for which were estimated to be on the order of 10(4)-10(5) years. These data suggested that dynamic speciation processes accompanied occasional spawning of new species and population size changes in this lake.
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Affiliation(s)
- Kaoru Maeda
- Department of Biology, Faculty of Sciences, Kyushu University, Ropponmatsu, Fukuoka 810-8560, Japan
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MICROSATELLITE POLYMORPHISM WITHIN TWO LAKE BAIKAL OILFISH SPECIES (COMEPHORUS LACEPEDE, 1801). ACTA ACUST UNITED AC 2007. [DOI: 10.17816/ecogen5250-57] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Intraspecific genetic polymorphism of a Baikal Lake endemic, big Baikal oilfish (Comephorus baicalensis Pallas, 1776), was evaluated based on microsatellite analysis. The obtained results have compared to the results received earlier for a little Baikal oilfish (C. dybowski Korotneff, 1905). Six microsatellite loci designed for the European sculpin, Cottus gobio, were used. Big Baikal oilfish samples were tested from the three Baikal trenches (southern, middle, northern). Average values of F<sub>ST</sub> and R<sub>ST</sub>indexes between the samples did not exceed 0,02 that point to weak intraspecific genetic differentiation. Big Baikal oilfish had the smaller allele variety, the greater deficit of heterozygotes and presence of low-molecular alleles in comparison with little Baikal oilfish. The values of genetic differentiation were equaled F<sub>ST</sub> = 0,138 and R<sub>ST</sub> = 0,244 for all loci between cumulative samples of little and big Baikal oilfish. Analysis of microsatellite polymorphism has showed that both a big and little Baikal oilfishes are represented by single populations. The factor promoting panmixia within the Baikal oilfish species is apparently a passive transfer of juvenile and adult fishes by water currents.
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Genner MJ, Nichols P, Carvalho GR, Robinson RL, Shaw PW, Turner GF. Reproductive isolation among deep-water cichlid fishes of Lake Malawi differing in monochromatic male breeding dress. Mol Ecol 2007; 16:651-62. [PMID: 17257120 DOI: 10.1111/j.1365-294x.2006.03173.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Male nuptial colour hues are important for the maintenance of reproductive isolation among cichlid fish species, and environmental changes that lead to narrower light spectra can lead to hybridization. However, cichlid species can naturally co-occur in narrow light spectrum habitats, such as turbid shallow lakes and the deep benthic zones of African rift lakes. Closely related species from narrow light spectrum habitats tend to differ little in the palette of male nuptial colours, thus for these taxa differences in colour patterns may be more important than differences in colour hue for species recognition. To investigate this hypothesis we examined morphometric and genetic differentiation among males of four sympatric putative species within the deep-water genus Diplotaxodon. These taxa live in a narrow-light spectrum environment where only blue light is present, and males differ primarily in 'monochromatic' black, white and silver patterning of the body and fins. Significant genetic differentiation was present among taxa in both microsatellite DNA and mitochondrial DNA, including one pair with no significant morphometric differentiation. Thus, these taxa represent reproductively isolated biological species, a result consistent with male nuptial patterning being important for species recognition and assortative mating. As such, we suggest that narrow-light spectra need not always represent barriers to effective visually mediated mate recognition.
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Affiliation(s)
- Martin J Genner
- Department of Biological Sciences, University of Hull, Hull HU6 7RX, UK.
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13
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Roy D, Docker MF, Haffner GD, Heath DD. Body shape vs. colour associated initial divergence in the Telmatherina radiation in Lake Matano, Sulawesi, Indonesia. J Evol Biol 2007; 20:1126-37. [PMID: 17465922 DOI: 10.1111/j.1420-9101.2006.01289.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Highly polymorphic colouration patterns are often associated with sexual selection in fish and can be the initial cause of divergence among closely related taxa. Here we use genetic, body colour and geometric morphometric data collected on 118 fish from Lake Matano, Sulawesi, Indonesia to test if colouration is the initial cause of divergence in the radiating Telmatherina genus. Results reveal that all Telmatherina previously described in this system can be categorized into three mitochondrial lineages and that colouration is only weakly associated with early divergence. Clade-specific body shapes, however, likely adapted to microenvironments are key to the initial divergence in this system. Data also show that although colourations were not likely instrumental in seeding divergence in these fish, they appear to have developed in parallel within each clade. Our results are consistent with an emerging pattern repeated in many vertebrate radiations, whereby divergence by colouration or other display traits is preceded by specialization to environmental adaptive peaks.
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Affiliation(s)
- D Roy
- Great Lakes Institute for Environmental Research, University of Windsor, Windsor, ON, Canada.
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Sefc KM, Baric S, Salzburger W, Sturmbauer C. Species-Specific Population Structure in Rock-Specialized Sympatric Cichlid Species in Lake Tanganyika, East Africa. J Mol Evol 2006; 64:33-49. [PMID: 17160645 DOI: 10.1007/s00239-006-0011-4] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2006] [Accepted: 10/16/2006] [Indexed: 10/23/2022]
Abstract
Species richness and geographical phenotypic variation in East African lacustrine cichlids are often correlated with ecological specializations and limited dispersal. This study compares mitochondrial and microsatellite genetic diversity and structure among three sympatric rock-dwelling cichlids of Lake Tanganyika, Eretmodus cyanostictus, Tropheus moorii, and Ophthalmotilapia ventralis. The species represent three endemic, phylogenetically distinct tribes (Eretmodini, Tropheini, and Ectodini), and display divergent ecomorphological and behavioral specialization. Sample locations span both continuous, rocky shoreline and a potential dispersal barrier in the form of a muddy bay. High genetic diversity and population differentiation were detected in T. moorii and E. cyanostictus, whereas much lower variation and structure were found in O. ventralis. In particular, while a 7-km-wide muddy bay curtails dispersal in all three species to a similar extent, gene flow along mostly continuous habitat appeared to be controlled by distance in E. cyanostictus, further restricted by site philopatry and/or minor habitat discontinuities in T. moorii, and unrestrained in O. ventralis. In contrast to the general pattern of high gene flow along continuous shorelines in rock-dwelling cichlids of Lake Malawi, our study identifies differences in population structure among stenotopic Lake Tanganyika species. The amount of genetic differentiation among populations was not related to the degree of geographical variation of body color, especially since more phenotypic variation is observed in O. ventralis than in the genetically highly structured E. cyanostictus.
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Affiliation(s)
- Kristina M Sefc
- Department of Zoology, Karl Franzens University of Graz, Universitätsplatz 2, A-8010 Graz, Austria
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Cruz R, Vilas C, Mosquera J, García C. The close relationship between estimated divergent selection and observed differentiation supports the selective origin of a marine snail hybrid zone. J Evol Biol 2005; 17:1221-9. [PMID: 15525407 DOI: 10.1111/j.1420-9101.2004.00802.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
To study the role of divergent selection in the differentiation of the two morphs in a hybrid zone of the intertidal snail Littorina saxatilis, we compared the strength of the divergent selection acting on a series of shell characters (as estimated by the viability of snails in a reciprocal transplant experiment) with the contribution of these characters to the phenotypic differences between the morphs. We found a close correlation between selection and differentiation, which suggests a cause-effect relationship, i.e. that all present differentiation is the result of past divergent selection. In addition, divergent selection was a very important component of the total natural selection acting on shell measures. These novel results support previous evidence, based on allozyme analysis, of a parapatric origin for this hybrid zone. We discuss possible limitations of this interpretation and the circumstances under which allopatric differentiation would produce the same results. Phenotypic analysis of divergent selection may be a useful method of investigating the evolutionary mechanisms involved in differentiation processes.
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Affiliation(s)
- R Cruz
- Departamento de Xenética, Facultade de Bioloxía, Universidade de Santiago de Compostela. Coruña, Galiza, Spain
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Pereyra R, Taylor MI, Turner GF, Rico C. Variation in habitat preference and population structure among three species of the Lake Malawi cichlid genus Protomelas. Mol Ecol 2004; 13:2691-7. [PMID: 15315681 DOI: 10.1111/j.1365-294x.2004.02224.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Several studies have demonstrated strong population structuring over small distances in the rocky-shore mbuna cichlid fishes from Lake Malawi, suggesting the potential for allopatric speciation. However, many endemic Lake Malawi cichlids are neither mbuna, nor confined to rocky shores. Using microsatellites, we investigated the population structure in three species of the non-mbuna genus Protomelas. The rocky-shore P. taeniolatus showed high levels of population structure even over distances of less than 1 km, while the sandy-shore species P. similis showed no significant structure over distances up to 21 km. Protomelas fenestratus, which is generally found at the interface between rocks and sand, also showed low levels of population structure. Our results suggest that the model of allopatric speciation based on habitat fragmentation within the current lake basin may be equally applicable to rocky-shore non-mbuna as to mbuna, but that an alternative model is required to explain speciation among sandy-shore species as well as the deep-water and pelagic species.
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Affiliation(s)
- Ricardo Pereyra
- School of Biological Sciences, University of East Anglia, Norwich NR4 7TJ, UK
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17
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Knight ME, Turner GF. Laboratory mating trials indicate incipient speciation by sexual selection among populations of the cichlid fish Pseudotropheus zebra from Lake Malawi. Proc Biol Sci 2004; 271:675-80. [PMID: 15209099 PMCID: PMC1691644 DOI: 10.1098/rspb.2003.2639] [Citation(s) in RCA: 92] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
It has been suggested that sexual selection may have played a major role in the rapid evolution of hundreds of species of cichlid fishes in Lake Malawi. We report the results of a laboratory test of assortative mating among Lake Malawi cichlid fishes from five closely related geographical populations differing in male courtship colour. Paternity of clutches was tested using microsatellite DNA typing of offspring. Out of 1955 offspring typed, 1296 (66.3%) were sired by the male from the same population as the female, which is more than three times the rate expected if females do not differentiate among males of the different populations (20%). This result indicates that mate preferences of geographical races are strongly differentiated, consistent with the races representing incipient geographical species diverging under sexual selection exerted by female preferences for different male courtship colours.
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Affiliation(s)
- Mairi E Knight
- Department of Biological Sciences, University of Hull, Hull HU6 7RX, UK
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Salzburger W, Meyer A. The species flocks of East African cichlid fishes: recent advances in molecular phylogenetics and population genetics. Naturwissenschaften 2004; 91:277-90. [PMID: 15241604 DOI: 10.1007/s00114-004-0528-6] [Citation(s) in RCA: 160] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
With more than 3,000 species, the fish family Cichlidae is one of the most species-rich families of vertebrates. Cichlids occur in southern and central America, Africa, Madagascar, and India. The hotspot of their biodiversity is East Africa, where they form adaptive radiations composed of hundreds of endemic species in several lakes of various sizes and ages. The unparalleled species richness of East African cichlids has been something of a conundrum for evolutionary biologists and ecologists, since it has been in doubt whether these hundreds of species arose by allopatric speciation or whether it is necessary to invoke somewhat less traditional models of speciation, such as micro-allopatric, peripatric, or even sympatric speciation or evolution through sexual selection mediated by female choice. Ernst Mayr's analyses of these evolutionary uniquely diverse species assemblages have contributed to a more direct approach to this problem and have led to a deeper understanding of the patterns and processes that caused the formation of these huge groups of species. We review here recent molecular data on population differentiation and phylogenetics, which have helped to unravel, to some extent, the patterns and processes that led to the formation and ecological maintenance of cichlid species flocks. It is becoming apparent that sexually selected traits do play an important role in speciation in micro-allopatric or even sympatric settings. Species richness seems to be roughly correlated with the surface area, but not the age, of the lakes. We observe that the oldest lineages of a species flock of cichlids are often less species-rich and live in the open water or deepwater habitats. While the species flocks of the Lake Malawai and the Lake Victoria areas were shown to be monophyletic, the cichlid assemblage of Lake Tanganyika seems to consist of several independent species flocks. Cichlids emerge as an evolutionary model system in which many fundamental questions in evolution and ecology can be tested successfully, yet for other fish species flocks the relative importance of alternative mechanisms of speciation is likely to differ from that in cichlid fish.
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Affiliation(s)
- Walter Salzburger
- Lehrstuhl für Zoologie und Evolutionsbiologie, Fachbereich Biologie, Universität Konstanz, 78457 Konstanz, Germany
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Arnegard ME, Kondrashov AS. SYMPATRIC SPECIATION BY SEXUAL SELECTION ALONE IS UNLIKELY. Evolution 2004. [DOI: 10.1554/03-419] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Allender CJ, Seehausen O, Knight ME, Turner GF, Maclean N. Divergent selection during speciation of Lake Malawi cichlid fishes inferred from parallel radiations in nuptial coloration. Proc Natl Acad Sci U S A 2003; 100:14074-9. [PMID: 14614144 PMCID: PMC283548 DOI: 10.1073/pnas.2332665100] [Citation(s) in RCA: 200] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2003] [Indexed: 11/18/2022] Open
Abstract
Repeated evolution of the same phenotypic difference during independent episodes of speciation is strong evidence for selection during speciation. More than 1,000 species of cichlids, >10% of the world's freshwater fish species, have arisen within the past million years in Lakes Malawi and Victoria in eastern Africa. Many pairs of closely related sympatric species differ in their nuptial coloration in very similar ways. Nuptial coloration is important in their mate choice, and speciation by sexual selection on genetically or ecologically constrained variation in nuptial coloration had been proposed, which would repeatedly produce similar nuptial types in different populations, a prediction that was difficult to test in the absence of population-level phylogenies. We measured genetic similarity between individuals within and between populations, species, and lake regions by typing 59 individuals at >2,000 polymorphic genetic loci. From these data, we reconstructed, to our knowledge, the first larger species level phylogeny for the most diverse group of Lake Malawi cichlids. We used the genetic and phylogenetic data to test the divergent selection scenario against colonization, character displacement, and hybridization scenarios that could also explain diverse communities. Diversity has arisen by replicated radiations into the same color types, resulting in phenotypically very different, yet closely related, species within and phenotypically highly similar yet unrelated sets of species between regions, which is consistent with divergent selection during speciation and is inconsistent with colonization and character displacement models.
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Affiliation(s)
- Charlotte J Allender
- Biodiversity and Ecology Division, University of Southampton, Bassett Crescent East, Southampton SO16 7PX, United Kingdom
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Smith PF, Konings A, Kornfield I. Hybrid origin of a cichlid population in Lake Malawi: implications for genetic variation and species diversity. Mol Ecol 2003; 12:2497-504. [PMID: 12919487 DOI: 10.1046/j.1365-294x.2003.01905.x] [Citation(s) in RCA: 82] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The importance of species recognition to taxonomic diversity among Lake Malawi cichlids has been frequently discussed. Hybridization - the apparent breakdown of species recognition - has been observed sporadically among cichlids and has been viewed as both a constructive and a destructive force with respect to species diversity. Here we provide genetic evidence of a natural hybrid cichlid population with a unique colour phenotype and elevated levels of genetic variation. We discuss the potential evolutionary consequences of interspecific hybridization in Lake Malawi cichlids and propose that the role of hybridization in generating both genetic variability and species diversity of Lake Malawi cichlids warrants further consideration.
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Affiliation(s)
- Peter F Smith
- Department of Biological Sciences, University of Maine, 5751 Murray Hall Orono, ME 04469-5751, USA
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