Relaxed trait covariance in interspecific cichlid hybrids predicts morphological diversity in adaptive radiations

O. M. Selz*, K. Lucek, K. A. Young, O. Seehausen

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

42 Citations (Scopus)
147 Downloads (Pure)

Abstract

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 Lakes Victoria and Malawi. 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.

Original languageEnglish
Pages (from-to)11-24
Number of pages14
JournalJournal of Evolutionary Biology
Volume27
Issue number1
Early online date16 Dec 2013
DOIs
Publication statusPublished - Jan 2014

Keywords

  • adaptive radiation
  • cichlid
  • hybridization
  • transgressive segregation
  • TRANSGRESSIVE SEGREGATION
  • INTROGRESSIVE HYBRIDIZATION
  • PHENOTYPIC CORRELATIONS
  • ECOLOGICAL OPPORTUNITY
  • AFRICAN CICHLIDS
  • GENETIC-VARIATION
  • SEXUAL SELECTION
  • FISH RADIATION
  • LAKE VICTORIA
  • SPECIATION

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