Study On The Sex Determination And Differentiation Of Rare Gudgeon (Gobiocypris Rarus) And The Advanced Method Of Its Breeding And Domestication

Rare gudgeon ( Gobiocypris rarus) is one of the rare minnow specially in China and a newly developed test organism , which has similar merits to some common experimental fishes and become a standardized test species for China,. This paper deals with several subjects about the sex determination and differentiation of rare gudgeon (Gobiocypris rarus) and the advanced method of its breeding and domestication.â…  Rare gudgeon was widely studied in genetics, development biology and environmental science, offering advantages that have been expounded in many recent publications. In brief, the high fecundity and small size of this fish, combined with rapid development and the extraordinary optical clarity of the embryo, allow highly effective embryology studies. Although great progress has been made in the studies on rare gudgeon, researches on the basic aspects of cellular genetics and molecular genetics still lag far behind. For this reason we made particular researches and descriptions about its breeding and domestication in this paper.â…¡ The karyotype formula of rare gudgeon is 2n=50 and sex chromosomes were not found.â…¢ The pachytene bivalents with G bands of rare gudgeon were obtained after the treatment with alkaline hypotonic solution and high concentration of chloroform fixative solution.â…£ Sry, the founder member in the Sox (Sry-related box) family that have sequence homology within the HMG (High Mobility Group, HMG) domain has been considered to be a strong candidate for the testis-determining factors. Sox genes are involved in a diverse range of developmental processes in early embryogenesis and were found to take part in sex determination, chondrogenesis, haemopoisis, neural development, lens development and so on of early embryogenesis. Using the primers,which specially amplify the conservative motif of the human Sry gene, we analyzed the Sox genes of rare gudgeon. Three amplification bands with the length 220, 700, 1500 bp respectively were observed. Two different fragments of Sox gene were selected and sequenced from fragments of the 220 bp band. There was no sex difference in the two fragments. The identity of amino acid sequence that encoded by GrSoxl to human and zebrafish is 96% and 98%. The amino acid sequence encoded by GrSox21 has about 88% and 100% identical to the human SOX21 and zebrafish SOX21.V Construction of phylogenetic trees is a key means in molecular evolutionary studies. Phylogenetic analysis of 92 Sox genes including Sry genes and the encoded amino acid sequences, which were obtained from the GenBank, MEBL and DDBJ database reveals that the Sox genes were highly conserved. The methods of constructing Phylogenetic trees include the distance-based methods, parsimony, maximum likelihood and Bayesian inference methods. Sox genes subdivided into ten subfamilies and all SRY/Sry of mammalian are grouped in subfamily Sox-Sl.This paper provides a brief introduction of principles of data selection and tree-construction methods and discuss about their advantage and disadvantage points.VI Two program were written to perfect the NCBI database in this paper.W Since the discovery in 1983, homebox genes, and the proteins they encode, the homeodomain proteins, have turned out to play important roles in the developmental processes of many multi-cellular organisms. While certainly not the only developmental control genes, they have been shown to play crucial roles from the earliest steps in embryogenesis - such as setting up an anterior-posterior gradient in the egg of the fruit fly - to the very latest steps in cell differentiation - such as the differentiation of neurons in the nematode Caenorhabditis elegans (C. elegans). They have a wide phylogenetic distribution, having been found in baker's yeast, plants, and all animal phyla that have been examined so far. Homeobox gene was also found in genome of rare gudgeon by PCR with the degenerate primers, which was designed within its conservative motif, and by blot hybridization.VH1 Sex determination genes may be detected by RAPD analysis among individuals of rare gudgeon. The distinct male and female genome of rare gudgeon was amplified with sixty select primers to discover the sex determined genes.