Newly discovered cichlid fish biodiversity threatened by hybridization with non-native species

Blackwell, Tabitha, Ford, Antonia G. P., Ciezarek, Adam G., Bradbeer, Stephanie J., Gracida Juarez, Carlos A., Smith, Alan M., Ngatunga, Benjamin P., Shechonge, Asilatu, Tamatamah, Rashid, Etherington, Graham, Haerty, Wilfried ORCID:, Di Palma, Federica, Turner, George F. and Genner, Martin J. (2021) Newly discovered cichlid fish biodiversity threatened by hybridization with non-native species. Molecular Ecology, 30 (4). pp. 895-911. ISSN 0962-1083

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Invasive freshwater fishes are known to readily hybridize with indigenous congeneric species, driving loss of unique and irreplaceable genetic resources. Here we reveal that newly discovered (2013–2016) evolutionarily significant populations of Korogwe tilapia (Oreochromis korogwe) from southern Tanzania are threatened by hybridization with the larger invasive Nile tilapia (Oreochromis niloticus). We use a combination of morphology, microsatellite allele frequencies and whole genome sequences to show that O. korogwe from southern lakes (Nambawala, Rutamba and Mitupa) are distinct from geographically disjunct populations in northern Tanzania (Zigi River and Mlingano Dam). We also provide genetic evidence of O. korogwe × niloticus hybrids in three southern lakes and demonstrate heterogeneity in the extent of admixture across the genome. Finally, using the least admixed genomic regions we estimate that the northern and southern O. korogwe populations most plausibly diverged ~140,000 years ago, suggesting that the geographical separation of the northern and southern groups is not a result of a recent translocation, and instead these populations represent independent evolutionarily significant units. We conclude that these newly discovered and phenotypically unique cichlid populations are already threatened by hybridization with an invasive species, and propose that these irreplaceable genetic resources would benefit from conservation interventions.

Item Type: Article
Additional Information: Funding Information: The work was funded by Royal Society‐Leverhulme Trust Africa Awards AA100023 and AA130107 to M.J.G., B.P.N. and G.F.T., BBSRC award BB/M026736/1 to G.F.T., M.J.G. and F.d.P., and BBSRC award BB/P016774/1 to W.H. and F.d.P. We thank the Tanzania Commission for Research and Technology (COSTECH) for fieldwork approval and permits, and staff of the Tanzania Fisheries Research Institute for contributions to fieldwork. We thank Nasser Kazosi for help with sample collection in Uganda, made under permit number IMP/GEN/2014/06. This research was supported in part by the NBI Computing infrastructure for Science (CiS) group through use of the CiS high‐performance computing cluster for the analysis of the whole genome resequence data. Publisher Copyright: © 2020 John Wiley & Sons Ltd
Uncontrolled Keywords: admixture,biodiversity conservation,cichlid fishes,geometric morphometrics,introgression,population genomics,ecology, evolution, behavior and systematics,genetics,sdg 15 - life on land ,/dk/atira/pure/subjectarea/asjc/1100/1105
Faculty \ School: Faculty of Science > School of Biological Sciences
Faculty of Medicine and Health Sciences > Norwich Medical School
Faculty of Science > The Sainsbury Laboratory
UEA Research Groups: Faculty of Medicine and Health Sciences > Research Centres > Norwich Institute for Healthy Aging
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Depositing User: LivePure Connector
Date Deposited: 16 Sep 2022 13:36
Last Modified: 07 Oct 2023 01:16
DOI: 10.1111/mec.15638


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