title: Novel microsatellite markers suggest the mechanism of parthenogenesis in Extatosoma tiaratum is automixis with terminal fusion.
abstract: Parthenogenetic reproduction is taxonomically widespread and occurs through various cytological mechanisms, which have different impact on the genetic variation of the offspring. Extatosoma tiaratum is a facultatively parthenogenetic Australian insect (Phasmatodea), in which females oviposit continuously throughout their adult lifespan irrespective of mating. Fertilized eggs produce sons and daughters through sexual reproduction and unfertilized eggs produce female offspring via parthenogenesis. Here, we developed novel microsatellite markers for E. tiaratum and characterized them by genotyping individuals from a natural population. We then used the microsatellite markers to infer the cytological mechanism of parthenogenesis in this species. We found evidence suggesting parthenogenesis in E. tiaratum occurs through automixis with terminal fusion, resulting in substantial loss of microsatellite heterozygosity in the offspring. Loss of microsatellite heterozygosity may be associated with loss of heterozygosity in fitness related loci. The mechanism of parthenogenetic reproduction can therefore affect fitness outcomes and needs to be considered when comparing costs and benefits of sex versus parthenogenesis.
authors.affiliation: School of BioSciences, University of Melbourne, Victoria, Australia.
authors.forename: Yasaman
authors.initials: Y
authors.lastname: Alavi
authors.affiliation: Cesar Pty Ltd, 293 Royal Parade, Parkville, Victoria, Australia.
authors.forename: Anthony
authors.initials: A
authors.lastname: van Rooyen
authors.affiliation: School of BioSciences, University of Melbourne, Victoria, Australia.
authors.forename: Mark Adrian
authors.initials: MA
authors.lastname: Elgar
authors.affiliation: School of BioSciences, University of Melbourne, Victoria, Australia.
authors.forename: Therésa Melanie
authors.initials: TM
authors.lastname: Jones
authors.affiliation: School of BioSciences, University of Melbourne, Victoria, Australia.|Cesar Pty Ltd, 293 Royal Parade, Parkville, Victoria, Australia.
authors.forename: Andrew Raymond
authors.initials: AR
authors.lastname: Weeks
mesh_terms: D000818:Animals; D005260:Female; D040582:Inheritance Patterns; D007313:Insecta / Q000502:physiology*; D008297:Male; D018895:Microsatellite Repeats; D010312:Parthenogenesis
keywords: Extatosoma tiaratum; apomixis; automixis; heterozygosity; microsatellite markers; parthenogenesis