Introgressive hybridization of tilapias in Zimbabwe

Gregg, Robert E.; Howard, James H.; Shonhiwa, F.

doi:10.1111/j.1095-8649.1998.tb01547.x

Cited by 18 publications

(18 citation statements)

References 28 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Natural hybridization of O. mossambicus with other parapatric Oreochromis species is also expected from the ease with which Tilapiine fish seem to hybridize. Support for this hypothesis is provided by (1) the observation that hybridization between tilapia species generally produces viable progeny (Wohlfarth and Hulata 1981), (2) the sympatric hybridization of Oreochromis in Western Africa mentioned above, and (3) hybridization in Zimbabwe between O. mossambicus or O. mortimeri and the allopatric species O. macrochir in the Upper Zambezi (Gregg et al 1998). …”

Section: Introductionmentioning

confidence: 84%

“…Understandably, the hybridization also occurs between species that overlap in geographical range, like O. mossambicus and O. andersonii (already detected by Gregg et al 1998). Of no less importance is the observation of several species outside their originally described geographic distribution, demonstrating a need for revision.…”

Section: Molecular Identification Of Hybrids and The Implications Formentioning

confidence: 91%

See 1 more Smart Citation

Hybridization and phylogeography of the Mozambique tilapia Oreochromis mossambicus in southern Africa evidenced by mitochondrial and microsatellite DNA genotyping

et al. 2006

View full text Add to dashboard Cite

Many Oreochromis species utilized in aquaculture were extensively introduced outside their native range in Africa. Given their recent evolutionary radiation, these species hybridize easily, posing a threat to the integrity of local adaptation. The objective of this work was to study the genetic diversity of the Mozambique tilapia (Oreochromis mossambicus) in its native range, southern Africa, and provide a method for identifying hybrids with genetic markers. We genotyped the mitochondrial DNA (mtDNA) control region (385 bp) of wild and farmed O. mossambicus, wild and farmed O. niloticus and morphologic wild hybrids. These data were complemented with published sequences of parapatric and sympatric Oreochromis taxa. Phylogeographic analysis showed the presence of two O. mossambicus lineages, the southernmost representing a recent Holocene radiation. Hybridization of O. mossambicus was indicated by the presence of O. niloticus and O. mortimeri-andersonii mtDNA specimens in the Limpopo basin and of O. karongae mtDNA in specimens from Malawi. We also genotyped seven suspected hybrid individuals from the Limpopo River, and 137 wild and farmed Mozambique and Nile tilapia samples with five microsatellite markers. Factorial Component Analysis, Bayesian clustering and assignment analyses consistently delineated an O. mossambicus and an O. niloticus group, with the putative hybrids positioned in between. Different levels of hybridization were detected by the Bayesian assignment. The complex nature of hybridization and introgression between cichlid species raises major concerns for the long-term integrity of Mozambique tilapia.

show abstract

Section: Introductionmentioning

confidence: 84%

Section: Molecular Identification Of Hybrids and The Implications Formentioning

confidence: 91%

Hybridization and phylogeography of the Mozambique tilapia Oreochromis mossambicus in southern Africa evidenced by mitochondrial and microsatellite DNA genotyping

et al. 2006

View full text Add to dashboard Cite

show abstract

“…Most samples showed significant departure from H–W equilibrium at one or more loci, except for sample OnaA (Table 5). The significant results of most samples were due to a significant deficit of heterozygous individuals, which is characteristic of two or more assertively mating populations which hybridize to some extent (Campton, 1987; Gregg et al, 1998). The deficit of heterozygotes was stronger in samples from Lake Metztitlan (OnsM and OnaM), followed by samples from EPS (OnrE, OnsE and OnaE) and Infiernillo (OnaI).…”

Section: Allele Frequencies and Genetic Variationmentioning

confidence: 99%

“…The high genetic variation ( H e ) in fish from Lake Metztitlan could be explained by their recent introduction and constant re‐stocking from two TFPF (Los Amates and Zacatepec) in the past 4 years. Hybridization or introgression in Lake Metztitlan may have taken place and deficiency of heterozygotes in one or more loci indicates this may have happened (Campton, 1987; Gregg et al, 1998). Introgression may also be taking place within the hybrid Rocky Mountain ( O. niloticus × O. aureus ) and the O. niloticus Stirling strain used in this study, and should be tested by analysing pure populations with other genetic markers.…”

Section: Genetic Variationmentioning

confidence: 99%

Variability of tilapias (Oreochromis spp.) introduced in Mexico: morphometric, meristic and genetic characters

et al. 2004

View full text Add to dashboard Cite

In Mexico, the tilapia Oreochromis provides one of the most important sources of animal protein and income in a wide variety of communities throughout the country, however, their culture and production face severe problems because of lack of management information. Evaluated in the present study is the degree of morphological, meristic and allozyme variation of two tilapia strains, two species and one hybrid from two important reservoirs in Mexico, two tilapia fry production farms (TFPF) and an experimental production system (EPS), to diagnose the actual status and degree of variation among them. Twenty-two presumptive loci were utilized to determine the genetic variation, structuring and distances among samples. Multivariate analyses of 11 meristic and 33 morphometric characters were also evaluated, including the distance from the end of the mouth opening to the most anterior dorsal fin (0.9894), distance from the anal fin base to the anterior part of the caudal fin (0.9845) and the base length of the dorsal fin (0.9839) which contributed to the separation of groups. The canonical discriminant functions for the morphometric and meristic variables show that the correct classification of the organisms in percentages and in the sites of origin was on average 72%. The tilapia from the reservoirs and the experimental production system had higher genetic variations than tilapia from the fry production farms (average H e 0.310, 0.062, 0.151 for Metztitlan, Infiernillo and EPS, respectively, vs 0.024 and 0.000 for Los Amates and Zacatepec, respectively). The genetic data indicate that fishes of the TFPF should be monitored closely, as they are the main source of dispersion to the reservoirs. Present results show that these data could be a fast and reliable aid to the fisheries and management of tilapia in Mexico.

show abstract

“…Anthropogenic translocations of Oreochromis within Africa were reported to induce several cases of interspecific hybridization leading to severe threats for the genetic integrity of native local species (e.g. [18], [19], [20], [21]). Moreover, recent studies investigating the transmission of hybrid genomes across generations have demonstrated that hybridization even between highly distantly related tilapia species can lead to classic meiotic processes with diploid Mendelian segregation and maintenance of a stable and recombining hybrid gene pool across generations [22].…”

Section: Introductionmentioning

confidence: 99%

Successive Invasion-Mediated Interspecific Hybridizations and Population Structure in the Endangered Cichlid Oreochromis mossambicus

Firmat

Alibert²,

Losseau³

et al. 2013

PLoS ONE

View full text Add to dashboard Cite

Hybridization between invasive and native species accounts among the major and pernicious threats to biodiversity. The Mozambique tilapia Oreochromis mossambicus, a widely used freshwater aquaculture species, is especially imperiled by this phenomenon since it is recognized by the IUCN as an endangered taxon due to genetic admixture with O. niloticus an invasive congeneric species. The Lower Limpopo and the intermittent Changane River (Mozambique) drain large wetlands of potentially great importance for conservation of O. mossambicus, but their populations have remained unstudied until today. Therefore we aimed (1) to estimate the autochthonous diversity and population structure among genetically pure O. mossambicus populations to provide a baseline for the conservation genetics of this endangered species, (2) to quantify and describe genetic variation of the invasive populations and investigate the most likely factors influencing their spread, (3) to identify O. mossambicus populations unaffected by hybridization. Bayesian assignment tests based on 423 AFLP loci and the distribution of 36 species-specific mitochondrial haplotypes both indicate a low frequency of invasive and hybrid genotypes throughout the system, but nevertheless reveal evidence for limited expansion of two alien species (O. niloticus and O. andersonii) and their hybrids in the Lower Limpopo. O. mossambicus populations with no traces of hybridization are identified. They exhibit a significant genetic structure. This contrasts with previously published estimates and provides rather promising auspices for the conservation of O. mossambicus. Especially, parts of the Upper Changane drainage and surrounding wetlands are identified as refugial zones for O. mossambicus populations. They should therefore receive high conservation priority and could represent valuable candidates for the development of aquaculture strains based on local genetic resources.

show abstract

Introgressive hybridization of tilapias in Zimbabwe

Cited by 18 publications

References 28 publications

Hybridization and phylogeography of the Mozambique tilapia Oreochromis mossambicus in southern Africa evidenced by mitochondrial and microsatellite DNA genotyping

Hybridization and phylogeography of the Mozambique tilapia Oreochromis mossambicus in southern Africa evidenced by mitochondrial and microsatellite DNA genotyping

Variability of tilapias (Oreochromis spp.) introduced in Mexico: morphometric, meristic and genetic characters

Successive Invasion-Mediated Interspecific Hybridizations and Population Structure in the Endangered Cichlid Oreochromis mossambicus

Contact Info

Product

Resources

About