Recent Advances in the Field of Parthenogenesis in Snakes
Booth, Warren
warren-booth@utulsa.edu
Department of Biological Science
The University of Tulsa
Tulsa, Oklahoma, USA
Chiricahua Desert Museum
Rodeo, New Mexico, USA
Card, Daren
Department of Organismic and Evolutionary Biology
Harvard University
Cambridge, Massachusetts, USA
Castoe, Todd A.
Department of Biology
University of Texas at Arlington
Arlington, Texas, USA
Vonk, Freek
Naturalis Biodiversity Center
Leiden, The Netherlands
Wüster, Wolfgang
Alistair Reid Venom Research Unit
School of Natural Sciences
Bangor University
Bangor, UK
Chiricahua Desert Museum
Rodeo, New Mexico, USA
Casewell, Nicholas R.
Liverpool School of Tropical Medicine
Liverpool, UK
Schuett, Gordon W.
Department of Biology and Neuroscience Institute
Georgia State University
Atlanta, Georgia, USA
Chiricahua Desert Museum
Rodeo, New Mexico, USA
In recent years it has become clear that snakes may represent an ideal model system for study of vertebrate parthenogenesis. Phylogenetically widespread, parthenogenesis has been reported as obligatory in the basal Brahminy Blind Snake (Indotyphlops braminus) and facultative in all of the other lineages. In those taxa demonstrated to exhibit facultative parthenogenesis (FP), a diversity of forms has been discovered with regard to characteristics of the resulting parthenogens. These include differences in sex chromosome morphology and number, viability, and sex of the parthenogens. This, in concert with the first records of viable reproduction by a parthenogen, has shed light on sex chromosome evolution which, in turn, has resulted in the identification of both ZW and XY sex chromosome systems in snakes. Recent findings in pitvipers have informed, and indeed yielded, additional questions regarding the inheritance and complexity of venom. Current research has focused on the levels of heterozygosity retained by individual parthenogens and the genomic regions of retention. New results in our labs bring into question the assumed mechanism of terminal fusion automixis as the pathway for producing FP progeny. This strongly suggests that our understanding of FP (and related phenomena) is likely far from complete.