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Relaxed trait covariance in interspecific cichlid hybrids predicts morphological diversity in adaptive radiations
Author(s) -
Selz O. M.,
Lucek K.,
Young K. A.,
Seehausen O.
Publication year - 2014
Publication title -
journal of evolutionary biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.289
H-Index - 128
eISSN - 1420-9101
pISSN - 1010-061X
DOI - 10.1111/jeb.12283
Subject(s) - biology , covariance , trait , cichlid , interspecific competition , interspecific hybrids , evolutionary biology , adaptive radiation , hybrid , ecology , genetics , statistics , phylogenetics , botany , gene , fish <actinopterygii> , fishery , computer science , programming language , mathematics
The process of adaptive radiation involves multiple events of speciation in short succession, associated with ecological diversification. Understanding this process requires identifying the origins of heritable phenotypic variation that allows adaptive radiation to progress. Hybridization is one source of genetic and morphological variation that may spur adaptive radiation. We experimentally explored the potential role of hybridization in facilitating the onset of adaptive radiation. We generated first‐ and second‐generation hybrids of four species of African cichlid fish, extant relatives of the putative ancestors of the adaptive radiations of L akes V ictoria and M alawi. We compared patterns in hybrid morphological variation with the variation in the lake radiations. We show that significant fractions of the interspecific morphological variation and the major trajectories in morphospace that characterize whole radiations can be generated in second‐generation hybrids. Furthermore, we show that covariation between traits is relaxed in second‐generation hybrids, which may facilitate adaptive diversification. These results support the idea that hybridization can provide the heritable phenotypic diversity necessary to initiate adaptive radiation.