Sexually dimorphic gene expression in the gonad and liver of shovelnose sturgeon (Scaphirhynchus platorynchus)

Abstract

The development of a biomarker for rapid detection of intersex is desirable to researchers and fisheries managers alike. The first step is to identify a marker that has a dimorphic expression pattern. With a focus on sex-specific genes, we assessed the use of vitellogenin (vtg), forkhead box L2 (foxl2) and doublesex and mab-3-related transcription factor 1 (dmrt1) as molecular biomarkers for the identification of gender in shovelnose sturgeon (Scaphirhynchus platorynchus), a species known to have intersex individuals. A total of 61 shovelnose sturgeons were sampled from the Wabash River, Indiana, in April 2008. Results from our study indicate that least 7.5% of the non-females had testicular oocytes. Expression level of liver vtg was not higher in females than males, nor was gonad dmrt1 expression found to be higher in males. Only the expression of foxl2 was significantly greater in females and was found to be useful for identifying gender. Variation in expression levels of foxl2 in gonads of intersex fish limited its usefulness as a single biomarker for identifying this condition. Instead, the use of foxl2 to dmrt1 (foxl2 transcript abundance/dmrt1 transcript abundance) may be useful in the identification of intersex fish, as this ratio increased with increased feminization. We conclude that foxl2 can be used to identify sex, but not intersex sturgeon.

Antagonists to the Wnt Cascade Exhibit Sex-Specific Expression in Gonads of Sexually Mature Shovelnose Sturgeon

“…2 A), which is similar to what has been previously reported for Acipenser fulvescens [Hale et al, 2010]. This is contrary to what has been previously reported by our lab, where we found that dmrt1 was expressed at about the same levels in male and female shovelnose sturgeon [Amberg et al, 2010]. Melt curve analysis in this study indicated 2 dmrt1 products in ovaries and generally only 1 in testes.…”

“…Fish were transported live to the Indiana Animal Disease Diagnostic Laboratory at Purdue University (West Lafayette, Ind., USA) where they were measured for fork length (mm), weighed (kg) and then euthanized with a lethal dose of FINQUEL MS-222 (Argent Chemical Laboratories, Inc., Redmond, Wash., USA). Sex of each fish was determined at the time of dissection and later corroborated based on histology (H&E staining as described in Amberg et al [2010]). Ovaries contained mature black eggs and testes sperm as described in Amberg et al [2010].…”

“…Sex of each fish was determined at the time of dissection and later corroborated based on histology (H&E staining as described in Amberg et al [2010]). Ovaries contained mature black eggs and testes sperm as described in Amberg et al [2010]. A small portion of each individual's gonad was collected, flash-frozen and stored at -80 ° C until further processing.…”

Discovery and identification of candidate sex-related genes based on transcriptome sequencing of Russian sturgeon (Acipenser gueldenstaedtii) gonads

“…Research suggests that the sex-determination system in sturgeons is ZW for female and ZZ for male (58). Sox9, dmrt1, TrA-1, and Foxl2 have been identified as biomarkers for sex determination in some sturgeons (2,3,24,26), but no biomarker has been identified in Russian sturgeons. A previous study found that the stFSHb subunit was expressed at a higher level in 3 and 4 yr old fish than in 1 yr old fish and that the expression level of stFSHb in females was significantly higher than in males (28).…”

Loss of <i>R-Spondin1</i> and <i>Foxl2</i> Amplifies Female-to-Male Sex Reversal in XX Mice

“…Nevertheless, evidence is accumulating to suggest that FOXL2 is an important ovarian differentiating gene. Indeed, its ovarian-specific expression is conserved in all vertebrate species studied until now [Loffler et al, 2003;Baron et al, 2004;Govoroun et al, 2004;Wang et al, 2004;Nakamoto et al, 2006;Liu et al, 2007;Rhen et al, 2007;Wotton et al, 2007;Alam et al, 2008;Ijiri et al, 2008;Oshima et al, 2008;Siegfried and Nusslein-Volhard, 2008;Nakamoto et al, 2009;Okada et al, 2009;Shi et al, 2009;Amberg et al, 2010;Moore et al, 2010;Shoemaker-Daly et al, 2010;Wu et al, 2010], and in an invertebrate species such as the pacific oyster [Naimi et al, 2009]. In addition to the function of Foxl2 in development, Foxl2 is also required for ovarian homeostasis.…”