Analysis Of Brain,dorsal Fin Transcriptome And Expression Of MRNAs And MiRNAs In Brain Of Discus Fish

The discus fish(Symphysodon haraldi)is native to the Amazon River in South America.Because of its gorgeous colors and elegant swimming,it is known as the "king of tropical ornamental fish" and is sought after by consumers all over the world.In recent years,discus fish have been farmed on a large scale in Southeast Asia,Europe,occupying an important position in the freshwater ornamental fish trade.Due to the complex reproduction and matching,the low spawning rate restricts the production efficiency in industrialization.In the growth and reproduction,in addition to the gonads,the brain plays an important role in the development of vertebrate gonads,gender regulation,and sexual behavior.Some male adult breeds have longer dorsal fin extensions.Sampling from fins can minimize the harm to fish.Therefore,in order to improve the industrialized production efficiency and the rapid development of the industry,research is necessary.Understanding the biological information of male and female brain tissues and dorsal fins of discus fish will help us understand the mechanism of sex difference genes in brain,and the genes involved in fin formation,which improves the apparent improvement and sex identification of ornamental fish.Furthermore,the large-scale reproduction and variety improvement of discus fish were further improved.The second-generation highthroughput sequencing technology was used to sequence the transcriptome of brain and dorsal fin of the discus fish.After high-quality original sequences were assembled and spliced,functional genes were annotated.Differentially expressed mRNAs were identified in brain.The genes related to gonadotropin-releasing hormone,luteinizing hormone,prolactin,and follicle-stimulating hormone were screened out.A combined miRNA and mRNA analysis was performed in brain.We screened genes related to fin formation and genes that may regulate longer dorsal fin elongation(drawing)in males.The conclusions and discussion are as follows:1.Transcriptome analysis of brain of discus fish:3 males and 3 females discus fish brain c DNA libraries were constructed and sequenced using the Illumina Hiseq 6000 platform.A total of 337190200 raw data were obtained from these 6 c DNA libraries.After quality screening,34109 genes and 67488 transcripts were properly obtained from 6 c DNA libraries.Gene-related functions were typically obtained by carefully comparing nr,GO,KEGG,Pfam,Swiss-Prot,and egg NOG data bases,and 85 were screened using statistical methods.Compared favorably with mature females,61 differential genes were up-regulated in male brain and 24 differential genes were down-regulated.MCH,Prlh,PITX2 DSCAM,IGCDC3,UNC93B1,and AKR1B1 are related to the formation of gonadotropin-releasing hormone,luteinizing hormone,prolactin,and follicle-stimulating hormone and gamete formation in discus fish.This study provided important basic data for the comparative study of brain sex differences in discus fish and the key regulation of the reproductive system.2.Transcriptome analysis of dorsal fin of dish fish3 males and 3 females dorsal fin c DNA libraries were constructed and sequenced using the Illumina Hiseq 6000 platform.A total of 323170182 raw data were obtained from these 6 c DNA libraries.After quality screening,34109 genes and 47999 transcripts were properly obtained from 6 c DNA libraries.Gene-related functions were typically obtained by carefully comparing nr,GO,KEGG,Pfam,Swiss-Prot,and egg NOG data bases,and 96 were screened using statistical methods.Compared favorably with mature females,21 differential genes were up-regulated in male brain and 85 differential genes were down-regulated.Including SERPINb1,Ang3,APOC1,COL9A1,which genes play an important role in dorsal fin formation of discus fish and dorsal fin extension of male fish.This study provides important basic data for sex identification of discus fish and fin improvement.3.Analysis of miRNA-mRNA regulatory network in male and female brain of discus fishThe Illumina Hiseq 2500 sequencing platform was used to obtain differentially expressed miRNAs from the male and female brains of discus fish.The brain miRNA-mRNA pair relationship network was constructed by two prediction algorithms(Target Scan 50 and mi Randa 3.3a).Integrate the results of the two algorithms and calculate the overlap.The study found that one miRNA corresponds to multiple target genes,and one target gene is regulated by multiple miRNAs.In order to explore the potential regulatory relationship between miRNAmRNA target genes related to gender differences in brain tissue,we used biologicalrelated methods to construct 61 function-related target gene pairs,forming a miRNAmRNA network relationship.