Hybridization in birds-of-paradise: Widespread ancestral gene flow despite strong sexual selection in a lek-mating system
Mozes P.K. Blom,
Valentina Peona,
Stefan Prost,
Les Christidis,
Brett W. Benz,
Knud A. Jønsson,
Alexander Suh,
Martin Irestedt
Affiliations
Mozes P.K. Blom
Department for Evolutionary Diversity Dynamics, Museum für Naturkunde, Leibniz Institute for Evolution and Biodiversity Research, 10115 Berlin, Germany; Department of Bioinformatics and Genetics, Swedish Museum of Natural History, 114 18 Stockholm, Sweden; Corresponding author
Valentina Peona
Department of Organismal Biology – Systematic Biology, Evolutionary Biology Centre, Science for Life Laboratory, Uppsala University, 752 36 Uppsala, Sweden
Stefan Prost
Ecology and Genetics Research Unit, University of Oulu, 90014 Oulu, Finland
Les Christidis
Faculty of Science and Engineering, Southern Cross University, Coffs Harbour, NSW 2450, Australia
Brett W. Benz
Department of Ecology and Evolutionary Biology and Museum of Zoology, University of Michigan, Ann Arbor, MI 48108, USA
Knud A. Jønsson
Natural History Museum of Denmark, University of Copenhagen, 1350 Copenhagen, Denmark; Department of Bioinformatics and Genetics, Swedish Museum of Natural History, 114 18 Stockholm, Sweden
Alexander Suh
Department of Organismal Biology – Systematic Biology, Evolutionary Biology Centre, Science for Life Laboratory, Uppsala University, 752 36 Uppsala, Sweden
Martin Irestedt
Department of Bioinformatics and Genetics, Swedish Museum of Natural History, 114 18 Stockholm, Sweden; Corresponding author
Summary: Sexual selection can directly contribute to reproductive isolation and is an important mechanism that can lead to speciation. Lek-mating is one of the most extreme forms of sexual selection, but surprisingly does not seem to preclude occasional hybridization in nature. However, hybridization among lekking species may still be trivial if selection against offspring with intermediate phenotypes prohibits introgression. Here we investigate this further by sequencing the genomes of nearly all bird-of-paradise (Paradisaeidae) species and 10 museum specimens of putative hybrid origin. We find that intergeneric hybridization indeed still takes place despite extreme differentiation in form, plumage, and behavior. In parallel, the genomes of contemporary species contain widespread signatures of past introgression, demonstrating that hybridization has repeatedly resulted in shared genetic variation despite strong sexual isolation. Our study raises important questions about extrinsic factors that modulate hybridization probability and the evolutionary consequences of introgressive hybridization between lekking species.
