The coincidence of ecological opportunity with hybridization explains rapid adaptive radiation in Lake Mweru cichlid fishes
Publisher DOI
Abstract
The process of adaptive radiation was classically hypothesized to require isolation of a
lineage from its source (no gene flow) and from related species (no competition).
Alternatively, hybridization between species may generate genetic variation that facilitates
adaptive radiation. Here we study haplochromine cichlid assemblages in two African Great
Lakes to test these hypotheses. Greater biotic isolation (fewer lineages) predicts fewer
constraints by competition and hence more ecological opportunity in Lake Bangweulu,
whereas opportunity for hybridization predicts increased genetic potential in Lake Mweru.
In Lake Bangweulu, we find no evidence for hybridization but also no adaptive radiation.
We show that the Bangweulu lineages also colonized Lake Mweru, where they hybridized
with Congolese lineages and then underwent multiple adaptive radiations that are strikingly complementary in ecology and morphology. Our data suggest that the presence of several related lineages does not necessarily prevent adaptive radiation, although it constrains the trajectories of morphological diversification. It might instead facilitate adaptive radiation when hybridization generates genetic variation, without which radiation may start much later, progress more slowly or never occur.
lineage from its source (no gene flow) and from related species (no competition).
Alternatively, hybridization between species may generate genetic variation that facilitates
adaptive radiation. Here we study haplochromine cichlid assemblages in two African Great
Lakes to test these hypotheses. Greater biotic isolation (fewer lineages) predicts fewer
constraints by competition and hence more ecological opportunity in Lake Bangweulu,
whereas opportunity for hybridization predicts increased genetic potential in Lake Mweru.
In Lake Bangweulu, we find no evidence for hybridization but also no adaptive radiation.
We show that the Bangweulu lineages also colonized Lake Mweru, where they hybridized
with Congolese lineages and then underwent multiple adaptive radiations that are strikingly complementary in ecology and morphology. Our data suggest that the presence of several related lineages does not necessarily prevent adaptive radiation, although it constrains the trajectories of morphological diversification. It might instead facilitate adaptive radiation when hybridization generates genetic variation, without which radiation may start much later, progress more slowly or never occur.
Date Issued
2019
Publication Type
Article
Subject(s)
Language(s)
en
Author(s)
Joyce, Domino A. | |
Mwaiko, Salome | |
Phiri, Numel | |
Schliewen, Ulrich K. | |
Katongo, Cyprian |
Journal
Nature communications
Publisher
Nature Publishing Group
ISSN
2041-1723
Access(Rights)
open.access