| Trachinotus blochii,common named Golden Pompano,inhabits mainly in South China Sea,the northern Indian Ocean,the Red Sea,the Atlantic coast,Mediterranean Sea and the coast of Africa.For the characteristics of fresh mouth feeling and fast growth,.blochii has been cultured on a large scale in the marine cage,and become one of the largest fish farming in the coastal areas of southern China.To meet the juvenile fish demand of culture industry,its artificial breeding is continuing to expand in Hainan,Guangdong,Guangxi and Fujian province in China.However,its genetical characterization began to decline,which caused by inbreeding gradually reveal in T.blochii.Therefore,the study on breeding of T.blochii is imminent.In order to understand growth traits and corresponding genetic background in T.blochii,its generation F1 family was established after the construction of the parentage identification technique platform.The optimal family was identified according to the correlation analysis of the morphological traits and body weight,and then QTLs related with growth traits were detected and located based on the contructed genetic linkage map.Finally,its gene expression in pituitary and liver was compared under the different temperature.This study has laid a solid basis for genetic breeding of T.blochii.1.Sevral brood stocks were selected through population reproduction to prepare Mixed-Family,and 11 high polymorphism Microsatellite Loci was used to build paternity test platform.After the genotyping of the offspring was detected using Gene Mapper 3.7 software,the parentage of gender module for unknown parents was identified with PAPA 2.0 software.The parents of 266 F2 progeny were identified(the identification rate is 92.4%).It is successfully set up 3 full-sib family of T.blochii.2.The relationships between morphological traits and body weight of two month T.blochii were studied with the correlation,stepwise linear regression,path analysis,variance and variability analysis.Full length was the first principal component,and its contribution rate reached 95.31%.The regression equation(Y= 0.043x1-0.838)of full length and body weight was established by the stepwise linear regression method.In the variance analysis of families,the family 1 had best performance on full length characters,and it could be used as an important target for follow-up selection and breeding.3.Total of 11,745 SNPs markers were selected by RAD-seq technology to construct the first high-density genetic linkage map of T.blochii.The map contained 24 linkage groups,and the genetic distance of male and female map was 4707.36(average length = 196.14 cM)and 5150.22 cM(average length = 214.60 cM),respectively.A total of 48 QTLs associated with the growth traits(full length,body weight and body height)were identified,including 7 QTLs associated with full length,29 QTLs associated with body weight and 12 QTLs associated with body height.4.The transcriptome differences in pituitary and liver of T.blochii under different temperatures(20 ℃,25 ℃)was analyzed using RNA-seq technology.Total of 187,277,583 high quality sequences were obtained,and assembled to obtain 100,495 Unigenes.After abundance estimation and difference examination,630 differentially expressed genes were obtained.There were 458 and 205 differentially expressed genes in pituitary and liver,respectively,and 33 differentially expressed genes were common.Furthermore,the expression of galanin receptor gene in pituitary is lower at 25 ℃.All the results indicated that galanin receptor regulated GH-IGF axis,and regulated the expression of trypsin,elastase,chymotrypsin and other digestive enzyme gene in liver,thus influences physiological processes such as the rate of lipid metabolism and the immune function of the body. |
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