Abstract: The gene expression patterns of Dmrt1,Amh,Cyp19a1a and Foxl2 involved in multiple sex determination in fish were compared between the male and female in tilapia Oreochromis niloticus,O.aureus and their hybrids（O.niloticus♀ × O.aureus♂） to research for sexual differentiation mechanim.The sexual differential expression levels of Dmrt1and Amh in tilapia O.niloticus and O.aureus were significantly or very significantly higher in testis than that in ovary（P 〈 0.05 or P 〈 0.01）,while Cyp19a1a and Foxl2 were expressed significantly higher in ovary than that in the testis（P 〈 0.05）.Sexual expression pattern of these genes in gonads of O.niloticus ♀ × O.aureus♂ was similar to that in their parents.There was higher expression of Dmrt1 in testis of O.aureus than that in O.niloticus and there was higher expression of Cyp19a1a and Foxl2 in ovary of O.aureus than that in O.niloticus.There were lower expression levels of the four genes in the gonads of O.niloticus × O.aureus than those in their parents in some degrees.It is speculated that inhibition of Cyp19a1a expression may be involved in high male rate of the tilapia hybrid offsprings.
2015, Vol. 30 
