| The laying performance of laying duck is an important index to measure its economic value,which mainly includes the age of first egg,egg production and egg quality.Through scientific and technological means,the candidate genes affecting the laying performance of laying ducks were found,and their laying performance could be significantly improved by molecular marker-assisted breeding.Genome-wide association study is to find candidate region and genes associated with target traits in the whole genome by next generation sequencing.This study is divided into two parts,the first part is the selection of Shaoxing duck,Shanma duck,Youxian Ma duck and Jinyun Ma duck four varieties of 1600 each,starting from the date of age of first egg,record its egg production every day,until the 66 weeks of age,and in 299 days of age,300 days of age and 301 days of age,each with different varieties of randomly selected 30 pieces of egg to measure egg quality,at last,through statistical analysis of four varieties of difference of laying performance.The second part is in 1600 Shaoxing ducks randomly choose 300 as genome-wide association study of the test object,the age of first egg and egg production record again,egg quality determination of as in the 299 days of age,300 days of age and 301 days of age for all 300 of duck eggs were measured,in the process of the test to remove the disqualification of egg quality determine and die,in the late collect blood samples,extraction of genomic DNA,tested to the genomic DNA extracted by the integrity,purity and concentration,the final sequence has 166 qualified samples,and then to shaoxing duck egg production traits of 11 indicators on genome-wide association analysis of screening candidate genes,providing theoretical support for high-quality new varieties breeding to in the future.1.Using IBM SPSS statistics 21.0 software to analyze the variance analysis of the age of first egg?egg production of the different week ages and egg quality of the four breeds,the difference between the indicators was analyzed by the method of LSD,and the correlation between the indexes was analyzed by correlation analysis.The eggs weight(66.46±0.79g)?Yolk Color(13.20±0.18)and Shell Strength(4.42±0.21)of Shaoxing duck were significantly higher than Jinyun Ma duck(P<0.05),shell Strength was significantly higher than Shanma duck(P<0.01),shell thickness was significantly higher than other breeds(P<0.01),total egg weight(17.72±0.21kg)was significantly higher than Jinyun Ma duck and Youxian Ma duck(P<0.01).In addition,the age of first egg of Shaoxing duck was the most late,but the total egg weight was highest in the age of 66 weeks,while the Youxian Ma duck was the earliest for the age of first egg,but the total egg weight and egg production in the 66 weeks was the fewest among four breeds,indicating that although age at first egg of shaoxing duck was late,but the duration of egg production and egg production rate was high,age at first egg of Youxian Ma duck was early,but there was premature aging.2.A genome-wide association analysis was conducted on the age of first egg,egg production and egg quality of shaoxing ducks by resequencing.A total of 10 SNPs significantly correlated with laying performance were detected in the genome,among which 4 SNPs were significantly correlated with age of first egg and 6 SNPs were significantly correlated with egg production of 66 weeks.All SNPs significantly correlated with the age of first egg were located on chromosome 2,one SNP was located in the MARCHF6 gene,and the other three SNPs were located 2?4kb upstream of MARCHF6 gene.On chromosome 2,four SNPs were significantly correlated with egg production of 66 weeks,all of which were located between CA2 and ATP6V0D2 genes.On chromosome 29,two SNPs were significantly correlated with egg production of 66 weeks,located at 1kb upstream of WDR18 gene and 75 bp downstream of GRIN3 B gene,respectively.Candidate genes such as MARCHF6,CA2,WDR18,and GRIN3 B were found near SNPs.No significant SNPS were associated with egg quality indicators. |
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