A recent discovery in reproductive endocrinology, the kisspeptin system has been found to play a pivotal role in the regulation of the brain-pituitary-gonadal axis. Kisspeptin signaling in the brain is vital to the onset of puberty, control and regulation of sex steroid production, and regulation of fertility and reproductive function in mammals. However, the importance of the kisspeptin system in other vertebrates, such as fish, is not as clear. The goal of the current study was to clone the kisspeptin genes (kiss1, kiss2, and the receptor kiss1ra) for the first time in the marine teleost Anoplopoma fimbria (sablefish), and explore their potential roles in gonadal development. Previously, expression of the kiss2 gene was demonstrated in the gonads of sablefish. Partial kiss mRNA sequences were obtained by PCR and rapid amplification of cDNA ends (RACE) cloning techniques. Semi-quantitative PCR assays developed for each gene allowed us to measure kiss1, kiss2 and kiss1ra mRNA levels in a variety of adult tissues. We found the highest abundance of these mRNAs in the gonads, brain, and pituitary. In particular, kiss2 mRNA was abundant in the ovary and appeared to be the most highly expressed of the kiss genes. We are currently analyzing the expression of the kiss genes in gonads of fish undergoing sexual differentiation. Preliminary data suggest that there is sexually dimorphic expression of all three genes early in life. The ultimate goal of this project is to determine if gonadal kiss gene expression plays an important role in sexual differentiation and/or gametogenesis in fish.