On the Origin of Lake Malawi Cichlid Species: A Population Genetic Analysis of Divergence

The cichlid fishes of Lake Malawi are famously diverse. However, phylogenetic and population genetic studies of their history have been difficult because of the great amount of genetic variation that is shared between species. We apply a recently developed method for fitting the "isolation with...

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Bibliographic Details
Published in:Proceedings of the National Academy of Sciences - PNAS 2005-05, Vol.102 (Suppl 1), p.6581-6586
Main Authors: Won, Yong-Jin, Sivasundar, Arjun, Wang, Yong, Hey, Jody
Format: Article
Language:English
Subjects:
Animal migration behavior
Animals
Biological Evolution
Biological taxonomies
Cichlids - classification
Cichlids - genetics
Colloquium Papers
Freshwater
Gene flow
Genetic loci
Genetic mutation
Genetic variation
Genetics, Population
Malawi
Models, Genetic
Molecular Sequence Data
Mutation - genetics
Polymorphism, Genetic - genetics
Population estimates
Population size
Probability
Speciation
Species Specificity
We they distinction
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Summary:The cichlid fishes of Lake Malawi are famously diverse. However, phylogenetic and population genetic studies of their history have been difficult because of the great amount of genetic variation that is shared between species. We apply a recently developed method for fitting the "isolation with migration" divergence model to a data set of specially designed compound loci to develop portraits of cichlid species divergence. Outgroup sequences from a cichlid from Lake Tanganyika permit model parameter estimates in units of years and effective population sizes. Estimated speciation times range from 1,000 to 17,000 years for species in the genus Tropheops. These exceptionally recent dates suggest that Malawi cichlids as a group experience a very active and dynamic diversification process. Current effective population size estimates range form 2,000 to near 40,000, and to >120,000 for estimates of ancestral population sizes. It appears that very recent speciation and gene flow are among the reasons why it has been difficult to discern the phylogenetic history of Malawi cichlids.
ISSN:0027-8424
1091-6490
DOI:10.1073/pnas.0502127102