title: A transcriptome derived female-specific marker from the invasive Western mosquitofish (Gambusia affinis).
abstract: Sex-specific markers are a prerequisite for understanding reproductive biology, genetic factors involved in sex differences, mechanisms of sex determination, and ultimately the evolution of sex chromosomes. The Western mosquitofish, Gambusia affinis, may be considered a model species for sex-chromosome evolution, as it displays female heterogamety (ZW/ZZ), and is also ecologically interesting as a worldwide invasive species. Here, de novo RNA-sequencing on the gonads of sexually mature G. affinis was used to identify contigs that were highly transcribed in females but not in males (i.e., transcripts with ovary-specific expression). Subsequently, 129 primer pairs spanning 79 contigs were tested by PCR to identify sex-specific transcripts. Of those primer pairs, one female-specific DNA marker was identified, Sanger sequenced and subsequently validated in 115 fish. Sequence analyses revealed a high similarity between the identified sex-specific marker and the 3´ UTR of the aminomethyl transferase (amt) gene of the closely related platyfish (Xiphophorus maculatus). This is the first time that RNA-seq has been used to successfully characterize a sex-specific marker in a fish species in the absence of a genome map. Additionally, the identified sex-specific marker represents one of only a handful of such markers in fishes.
authors.affiliation: University of Innsbruck, Research Institute for Limnology, Mondsee, Austria.
authors.forename: Dunja K
authors.initials: DK
authors.lastname: Lamatsch
authors.affiliation: Uppsala University, Department of Evolutionary Biology, Evolutionary Biology Centre, Uppsala, Sweden.
authors.forename: Sofia
authors.initials: S
authors.lastname: Adolfsson
authors.affiliation: University of Otago, Department of Zoology, Dunedin, New Zealand; University of Sydney, Charles Perkins Centre / School of Biological Sciences, Sydney, New South Wales, Australia.
authors.forename: Alistair M
authors.initials: AM
authors.lastname: Senior
authors.affiliation: University of Innsbruck, Research Institute for Limnology, Mondsee, Austria.
authors.forename: Guntram
authors.initials: G
authors.lastname: Christiansen
authors.affiliation: University of Innsbruck, Research Institute for Limnology, Mondsee, Austria.
authors.forename: Maria
authors.initials: M
authors.lastname: Pichler
authors.affiliation: University of Otago, Department of Zoology, Dunedin, New Zealand.
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Ozaki
authors.affiliation: Uppsala University, Department of Evolutionary Biology, Evolutionary Biology Centre, Uppsala, Sweden.
authors.forename: Linnea
authors.initials: L
authors.lastname: Smeds
authors.affiliation: University of Würzburg, Physiological Chemistry, Biocenter, Würzburg, Germany.
authors.forename: Manfred
authors.initials: M
authors.lastname: Schartl
authors.affiliation: University of Otago, Department of Zoology, Dunedin, New Zealand.
authors.forename: Shinichi
authors.initials: S
authors.lastname: Nakagawa
mesh_terms: D000818:Animals; D003532:Cyprinodontiformes / Q000235:genetics*; D017931:DNA Primers / Q000235:genetics; D005260:Female; D005819:Genetic Markers / Q000235:genetics*; D008297:Male; D010802:Phylogeny; D017423:Sequence Analysis, RNA / Q000379:methods; D012730:Sex Chromosomes / Q000235:genetics; D012732:Sex Determination Analysis / Q000379:methods; D019849:Sex Determination Processes / Q000235:genetics*; D059467:Transcriptome / Q000235:genetics*
chemical_list: D017931:DNA Primers; D005819:Genetic Markers