Screening Of Different Express Sex-related Genes And Changes Of Serum Hormones Level In Monopterus Albus

Firstly, we sequenced the transcriptome of gonad and brain in ricefiled eel Monopterus albus, and obtained1,953,000pieces of unigenes. According to the analysis of function annotation and pathway enrichment of these unigenes, different expression unigenes in gonad among three genders were much more than those in brain, moreover, differences between intersex and male gonad were more significant than that between female and intersex gonad. Quantity biases of unigenes pointed out a more potential research direction in the sequential studies. The results of analysis in unigenes pathway enrichment revealed that the sex reverse in M. albus was closedly related to cell cycle and cell apoptosis signal pathway.Secondly, we screened many different express genes in the gonad of M. albus, and successfully cloned one kind of17β-HSD, which mainly expressed in female and intersex gonad. After nucleotide and amino acid sequence alignment with other species, this kind of17α-HSD belonged to17β-HSD12-A with the function to catalyze estrone to estradiol. Another cloned gene was DMC1, which significantly expressed only in intersex gonad. Previous study in DMC1indicated it only expressed in the beginning of meiotic in gonad cells. The conservation of DMC1revealed that it was an ideal accurate molecular marker to indicate the just beginning of the sex reverse of M. albus from female to intersex.Finally, we measured the hormones concentration in serum in different genders including testosterone (T), estradiol (E2), thyroxine (T4), triiodothyronine (T3), cortisol and also blood glucose. The results showed that serum T level firstly significantly dropped when ricefield eel developed from female to intersex (p<0.05), and then significantly increased from intersex to male (p<0.05). While serum E2level only significantly decreased from intersex to male (p<0.05). Moreover, serum T3remained the same level among different genders, and T4showed the same change trend as T3. Serum cortisol level was significantly higher in female and intersex than that in male. Blood glucose also showed the same level among different genders. The results indicated that E2and T level both positively associated with the development of ovary and testes of M. albus, respectively. While thyroid hormones and cortisol probably indirectly affected gonad development through energy metabolism regulation or other means.