%0 Journal Article
%T Sex differentiation in Atlantic cod (Gadus morhua L.): morphological and gene expression studies
%A Trine Haugen
%A Fernanda F.L. Almeida
%A Eva Andersson
%A Jan Bogerd
%A Rune Male
%A Katrine S Skaar
%A R邦diger W Schulz
%A Elin Sˋrhus
%A Tim Wijgerde
%A Geir L Taranger
%J Reproductive Biology and Endocrinology
%D 2012
%I BioMed Central
%R 10.1186/1477-7827-10-47
%X Gonads were examined histologically in juveniles from 14 to 39ˋmm total body length (TL). Number and size of germ cells were determined in a subset of the samples. Relevant genes were cloned, and mRNA levels determined by qPCR of amh, cyp19a1a; dax1 (nr0b2); shp (nr0b2a) and sox9b in a mixed-sex and an all-female population ranging from 12每49ˋmm TL.Individuals between 14每20ˋmm TL could be separated in two subgroups based on gonad size and germ cell number. Ovarian cavity formation was observed in some individuals from 18每20ˋmm TL. The mixed sex population displayed bimodal expression patterns as regards cyp19a1a (starting at 12ˋmm TL) and amh (starting at 20ˋmm TL) mRNA levels. After approximately 30ˋmm TL, cyp19a1a and amh displayed a gradual increase in both sexes. No apparent, sex-dependent expression patterns were found for dax1, shp or sox9b transcripts. However, shp levels were high until the larvae reached around 35ˋmm TL and then dropped to low levels, while dax1 remained low until 35ˋmm TL, and then increased sharply.The morphological sex differentiation in females commenced between 14每20ˋmm TL, and ovarian cavities were evident by 18每20ˋmm TL. Testis development occurred later, and was morphologically evident after 30ˋmm TL. This pattern was corroborated with sexually dimorphic expression patterns of cyp19a1a from 12每13ˋmm TL, and a male-specific increase in amh from 20ˋmm TL.
%K Atlantic cod
%K Sex differentiation
%K Aromatase
%K cyp19a1a
%K Anti-m邦llerian hormone
%K amh
%K dax1
%K shp
%K Masculinization
%U http://www.rbej.com/content/10/1/47/abstract