Polymorphisms Screening Of MiRNA Seed Region And Expression Profile Constructing Of MiR-1657in Chicken

The purpose of the study was to screen the SNP in miRNA seed region, and analyze theeffect of the SNP on economic trait, and the expression patterns of miRNA gene in the different tissues ofchicken. In the present research, bioinformatics method was used to screen the SNPs within miRNA seedregion. A total of860chickens from a Gushi-Anka F2resource population created by Henan InnovativeEngineering Research Center of Poultry Germplasm Resources were used as the experiment material.Adopting DNA pool, DNA sequencing technology and polymerase chain reaction-restriction fragmentlength polymorphism (PCR-RFLP) technologies to screen the SNP existed in the population, and analyzethe relationships between genetic variations and related economic traits in the chicken. Both additive anddominant effects were conducted to select the significant miRNAs-seed-SNP. Real-time PCR was used todetect the expression of miRNAs and the host gene in different tissues, and miRNA over expressionvector was constructed to provide basic for the further function study.The main results are as follows:PartⅠ、Combining online software and bioinformatics analysis, eight SNPs occurring within miRNAseed region was available.Part Ⅱ、 Three SNPs occurring within miRNA seed region as gga-miR-1644（+3T>C）,gga-miR-1614-3p（+5G>A）and gga-miR-1657（+6G>A）were found in the Gushi-Anka F2resourcepopulation. Population genetics analysis showed that+3T>C didn’t belong to Polymorphic loci（PIC<0.1）. The related analysis between gga-miR-1614-3p（+5G>A）and gga-miR-1657（+6G>A）and meat quality, growth trait, carcass trait, muscle fiber character and blood biochemical index wereperformed. The results indicated that+6G>A was significant with chicken2and8weeks body weight,12weeks shank girth,12weeks body slanting length,4weeks pelvis breadth and roundness of breastmuscle fiber, aspect ratio of breast muscle fiber and plumpness rate of breast muscle fiber（P <0.05）,highly significant with4,6,10and12weeks body weight, Length of breast muscle fiber（P <0.01）, andhad significant additive effects with most significant traits（P <0.05）. The association analysis results showed that the SNP rs15172520was significantly associated with breast muscle shear force, leg musclewater loss rate and wing weight, heart weight（P <0.05）, and highly significantly associated with theweight of the abdominal fat（P <0.01）.Part Ⅲ、The analysis results of different tissue expression of miR-1657and its host genes Rab38inGushi chickens for2weeks and36weeks showed that: in jejunum, glandular stomach, brain, heart,muscular stomach, hypothalamus, leg muscle and lungs, miR-1657was significant higher expression at2weeks than36weeks（P <0.05）, high tissue specificity was show in hypothalamus. Rab38gene wassignificant higher expression at2weeks than36weeks（P <0.05）in kidney, and the expression trend ofRab38was accordance to miR-1657in hypothalamus, jejunum, glandular stomach, heart and leg muscle.Therefore, we speculated that miR-1657and Rab38maybe co-expression.Part Ⅳ、In this study，we successfully constructed the expression vector pcDNA3.1（+）-pre-miR-1657, which provides the basis for the further function study of miR-1657in vitro.