| Duck varieties are rich in China,but the local duck varieties are mature late,poor egg production and can not meet the increasing market demand.The egg production is a low heritability trait,which is difficult to be improved by conventional breeding methods.Molecular marker assisted selection provides a new method for improving livestock and poultry traits.In this study,using GnIH,GnIHR,MTNR1 A,MTNR1B and OTX2 as candidate genes.The candidate genes were detected by PCR-RFLP,and analyzed the correlation between the loci and the laying traits and egg quality traits of ducks.The main results of this study are as follows:(1)Five SNP causing the change of restriction sites in GnIH gene were screened.The-1325G>C site was significantly associated with egg shell strength and egg shape index(P <0.05).The 1799A>G site of intron 1 was significantly associated with body weight at sexual maturity,age at first laying,egg production at 240 day,egg proportion(P <0.05).The 2041C>T site in exon 2 was significantly associated with body weight at sexual maturity,age at first laying,egg proportion(P <0.05).The 3328G>A downstream of the gene was very significantly associated with age at first laying and egg production at 150 days(P <0.01),which was significantly associated with egg production from 180 to 300 days(P <0.05).The regulatory transcription factor CDP CR1 was found at 3328G>A site.(2)In GnIHR gene,the-40A>G site was significantly associated with the egg production at 210,240,300day(P <0.05).The 113G>A site was significantly associated with the number of egg production at 210 day,52 week and 330 days(P <0.05).The 2676T>C site was missense mutation,and was very significantly associated with egg production at 120 day and egg yolk color(P <0.01),this site was significantly associated with body weight at sexual maturity,age at first laying,egg production from150 to 240 days(P <0.05).1587T>C and 1838C>T were not significantly associated with laying traits and egg quality traits(P> 0.05).(3)In MTNR1 A gene's exon 3 3887A>G site was missense mutation,which was very significantly associated with egg production at 510 day(P <0.01),and was significantly associated with egg production at 480 day,egg shell strength(P <0.05).314A>G,809G>C and 1935T>C sites were not significantly associated with the layig traits and egg quality traits(P> 0.05).(4)In MTNR1 B the 112C>G site was significantly associated with Haugh unit(P <0.05).The 34093A>G site was associated with age at first laying,egg production at 150 day and 180 day,egg shape index significantly(P <0.05).The 35602A>C and 35782G>A sites were not significantly associated with the laying traits and egg quality traits(P> 0.05).(5)The 1796T>A site of OTX2 gene was significantly associated with the age at first laying,first egg weight and egg shell strength(P <0.05).The 2036A>G site was significantly associated with age at first laying(P <0.01).The 2083G>A site was very significantly associated with the age at first laying(P <0.01),and associated with first egg weight,egg production at 210 and 240 day significantly(P <0.05).2980T>A site was a missense mutation site in exon3,which was egg shell strength(P <0.05).The 3016G>A site was in the 3'UTR region,and was significantly associated with age at first egg,egg shell strength,Haugh units(P <0.05).(6)The combination of 3328G>A site in GnIH and 2083G>A site in OTX2 b gene was significantly associated with the age at first laying(P <0.05),the advantage combination is AA-GG.The 2036A>G site in OTX2 gene and 113G>A site in GnIHR,2083G>A site in OTX2 gene and 113G>A GnIHRa genes were associated with age at first laying very significantly(P <0.01),the dominant genotype combinations were AA-GG and GG-GG,respectively.The combination of 34093A>G site in MTNR1 B gene and 113G>A site GnIHR gene was significantly associated with the body weight at sexual maturity(P <0.05).The combination of 2036A>G site in OTX2 gene and 34093A>G site in MTNR1 B gene was significantly associated with the first egg wgg(P <0.05). |
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