Sex determination and differentiation of the siberian sturgeon

Abstract

This is a synthesis of the published information on sex determination and differentiation in sturgeons with special emphasis in Siberian sturgeon Acipenser baerii. The sex-determination system has been poorly studied in sturgeons and paddlefishes. Among 27 species of Acipenseriformes, the WZ-female model has been proposed in five species and one hybrid based on gynogenetic studies. The sex-determining gene remains unknown, and there are no studies on the influence from autosomal genetic factors or environmental cues. The lack of genetic sex marker is limiting the studies on sex determination and differentiation, as well as the application in the early sexing for culture purposes. The gonad sex differentiation show similar histological features in different sturgeons studied and occur at juvenile stage (4-9 months of age). Siberian sturgeon reach the sex differentiation around the 8 months of age when reared in a range of temperature of 14-19 °C, coincident with the upper range of spawning temperature of species at wild. However, the potential effect of temperature on sex determination has not been studied in sturgeons. The molecular sex differentiation period precedes the sex differentiation and occurs between 3 and 6 months old in Siberian sturgeons. The factors involved in male and female pathways are currently studied at molecular level. Gonad transcriptomes are emerging in sturgeons stimulating the knowledge of factors that must direct a cascade of gene regulatory controls that provide sex-specific phenotypes. There is a lack of functional studies in sturgeons.