title: Facultative parthenogenesis in a critically endangered wild vertebrate.
abstract: Facultative parthenogenesis - the ability of sexually reproducing species to sometimes produce offspring asexually - is known from a wide range of ordinarily sexually reproducing vertebrates in captivity, including some birds, reptiles and sharks [1-3]. Despite this, free-living parthenogens have never been observed in any of these taxa in the wild, although two free-living snakes were recently discovered each gestating a single parthenogen - one copperhead (Agkistrodon contortrix) and one cottonmouth (Agkistrodon piscivorus) [1]. Vertebrate parthenogens are characterized as being of the homogametic sex (e.g., females in sharks, males in birds) and by having elevated homozygosity compared to their mother [1-3], which may reduce their viability [4]. Although it is unknown if either of the parthenogenetic snakes would have been carried to term or survived in the wild, facultative parthenogenesis might have adaptive significance [1]. If this is true, it is reasonable to hypothesize that parthenogenesis would be found most often at low population density, when females risk reproductive failure because finding mates is difficult [5]. Here, we document the first examples of viable parthenogens living in a normally sexually reproducing wild vertebrate, the smalltooth sawfish (Pristis pectinata). We also provide a simple approach to screen any microsatellite DNA database for parthenogens, which will enable hypothesis-driven research on the significance of vertebrate parthenogenesis in the wild.
authors.affiliation: School of Marine and Atmospheric Science, Stony Brook University, Stony Brook, NY 11794, USA.
authors.forename: Andrew T
authors.initials: AT
authors.lastname: Fields
authors.affiliation: Pritzker Laboratory for Molecular Systematics and Evolution, Field Museum of Natural History, 1400 South Lake Shore Drive, Chicago, IL 60605, USA.
authors.forename: Kevin A
authors.initials: KA
authors.lastname: Feldheim
authors.affiliation: Florida Fish and Wildlife Conservation Commission, Fish and Wildlife Research Institute, Charlotte Harbor Field Laboratory, 585 Prineville Street, Port Charlotte, FL 33954, USA.
authors.forename: Gregg R
authors.initials: GR
authors.lastname: Poulakis
authors.affiliation: School of Marine and Atmospheric Science, Stony Brook University, Stony Brook, NY 11794, USA. Electronic address: demian.chapman@stonybrook.edu.
authors.forename: Demian D
authors.initials: DD
authors.lastname: Chapman
mesh_terms: D000818:Animals; D056727:Endangered Species; D005260:Female; D008297:Male; D010312:Parthenogenesis; D012860:Skates, Fish / Q000502:physiology*