title: The evolution of peafowl and other taxa with ocelli (eyespots): a phylogenomic approach.
abstract: The most striking feature of peafowl (Pavo) is the males' elaborate train, which exhibits ocelli (ornamental eyespots) that are under sexual selection. Two additional genera within the Phasianidae (Polyplectron and Argusianus) exhibit ocelli, but the appearance and location of these ornamental eyespots exhibit substantial variation among these genera, raising the question of whether ocelli are homologous. Within Polyplectron, ocelli are ancestral, suggesting ocelli may have evolved even earlier, prior to the divergence among genera. However, it remains unclear whether Pavo, Polyplectron and Argusianus form a monophyletic clade in which ocelli evolved once. We estimated the phylogeny of the ocellated species using sequences from 1966 ultraconserved elements (UCEs) and three mitochondrial regions. The three ocellated genera did form a strongly supported clade, but each ocellated genus was sister to at least one genus without ocelli. Indeed, Polyplectron and Galloperdix, a genus not previously suggested to be related to any ocellated taxon, were sister genera. The close relationship between taxa with and without ocelli suggests multiple gains or losses. Independent gains, possibly reflecting a pre-existing bias for eye-like structures among females and/or the existence of a simple mutational pathway for the origin of ocelli, appears to be the most likely explanation.
authors.affiliation: Department of Biology, University of Florida, Gainesville, FL, USA Jilin Key Laboratory of Animal Resource Conservation and Utilization, Northeast Normal University, Changchun, China.
authors.forename: Keping
authors.initials: K
authors.lastname: Sun
authors.affiliation: Department of Biology, University of Florida, Gainesville, FL, USA.
authors.forename: Kelly A
authors.initials: KA
authors.lastname: Meiklejohn
authors.affiliation: Department of Ecology and Evolutionary Biology, University of California, Los Angeles, CA, USA.
authors.forename: Brant C
authors.identifier: http://orcid.org/0000-0002-1943-0217
authors.initials: BC
authors.lastname: Faircloth
authors.affiliation: Department of Environmental Health Science, University of Georgia, Athens, GA, USA.
authors.forename: Travis C
authors.initials: TC
authors.lastname: Glenn
authors.affiliation: Department of Biology, University of Florida, Gainesville, FL, USA.
authors.forename: Edward L
authors.identifier: http://orcid.org/0000-0003-1643-5212
authors.initials: EL
authors.lastname: Braun
authors.affiliation: Department of Biology, University of Florida, Gainesville, FL, USA rkimball@ufl.edu.
authors.forename: Rebecca T
authors.identifier: http://orcid.org/0000-0001-5449-5481
authors.initials: RT
authors.lastname: Kimball
mesh_terms: D000818:Animals; D001483:Base Sequence; D005075:Biological Evolution; D005241:Feathers / Q000033:anatomy & histology; D005260:Female; D046094:Galliformes / Q000145:classification* / Q000235:genetics*; D008297:Male; D008969:Molecular Sequence Data; D010802:Phylogeny; D010858:Pigmentation / Q000235:genetics*
keywords: eyespots; homology; ocelli; sexual selection; ultraconserved elements