Involvement Of Mitfa Gene In Body Color Formation Of The Ornamental Fish

Color phenotype is an important feature of the ornamental fish. The research in the occurrence differentiation, migration and material transportation of pigment cells contributes to the research in color formation and development in ornamental fish. By doing the research about the development and genetics of body color, we could understand the genetic mechanism of ornamental fish pigment genes. So that we could effectively predict and control the design and color in the breeding.In this paper, Cryprinus carpiod which was an important ornamental fish was used to investigate. This article mainly consists of three parts: fish body color development, pigment cell, assaying of mitf gene in molecular level. Mitf gene is one of pioneer biomarkers of differentiation from neural crest cell to melanin in mammals, and it could regulate the melanin cell’s development and differentiation. We have known the expression level of mitf gene in the four kinds of kio carp(Procypris merus, Yamabaki ogon., Taisho sane, Taisho sank) and different development period of T.sank for the further study in the role of ontogenesis mitf gene in fish.In this article, mitfa cDNA has been first cloned from the Japanese ornamental (Koi) carp (Cyprinus carpio L.), which is an important ornamental freshwater fish. The full-length cDNA of mitfa gene is1634bp, coding for412amino acids in the Koi. The identity degree of MITFa amino acid sequences between the Koi carp and the zebrafish is92.9%.Then, we found four types and distribution of pigment cells in kio carp, they are melanocytes, erythrocytes, xanthophores and iridocytes. The body color is black or with white splash in the P. merus. There are three kinds of the pigment cells:melanophore, iridophore and xanthophore in the tissues of skin, scales or fins of P. merus, which lacks of erythropore. The body color of T. sanke is white with red and black splash, which the melanophore, erythropore, xanthophore and iridophore are observed in it’s skin, scales and fins. Kohaku have some red spots on white body, in which are consis of erythropore and xanthophore, but melanophore was not observed. The whole of body color Y. ogon is yellow, there have abundant erythropores and xanthophores in its skin, scales and fins. This paper observed the T.sanke and Kohaku’s early individual process in the formation and development. Xathophores are founded on the3day after hatching. The number of xathophores increase, and they gradually appear from the head to tail in the fry of T. sanke. Melanophores are first observed after12-day-old, and amplicated after24-day-old, which are widely distributed in the whole body. After27-day-old, body melanin cells counts, the color becomes shallow, melanin cell concertration distribution in the area of place which will develop into a black part. The iridocytes are emerged on the belly after15-day-old. After35-day-old xanthophores develop into adult form, the part degenerated from the melanin cell becomes into transparent.It revealed that the mitfa gene is high expressed in the skin of T. sanke and P. Merus. The mitfa gene was also expressed in the Kohaku and Y. Ogon which contain no melanocyte. It shows that a low lever of mitfa mRNA was expressed in the early blastula, while there is high expression of mitfa mRNA after hatching in Taisho sanke. Our results show that the mitfa gene is involved in the regulation of fish body color.