| In this study,the Wumeng crested chickens were used as the experimental animals,and the program of conservation and breeding was developed and implemented.The growth index,reproduction index of the zero-generation and the growth performance of the first-generation brooding period were measured respectively;Secondly,QDPR gene and RBP4 A gene were selected as candidate genes,and the single nucleotide polymorphisms of QDPR gene and RBP4 A gene were analyzed by direct sequencing technology to find the genetic markers related to the growth and reproduction performance of Wumeng crested chickens.Finally,Real-time quantitative PCR technique was used to detect the m RNA expression differences of QDPR and RBP4 A genes in different tissues at different growth stages of Wumeng crested chickens.The results are as follows:1.To formulate the program of conservation and breeding and establish a zerogeneration core group in Wumeng crested chickens,36 families of Yellow plumage chicken and 72 families of Linen plumage chicken were selected.The test results of production performance showed that the growth performance of 16～45 week old yellow plumage rooster was better than that of Linen plumage roosters,but there was no significant difference between them(P>0.05).And the width of pelvis of 16 week old Yellow plumage hens was significantly larger than that of Linen plumage hens(P<0.01).The body length and chest width of 43 week old yellow feather hens were significantly higher than those of Linen plumage hens(P<0.05);The age at first egg of Linen plumage families was significantly earlier than that of Yellow plumage families(P<0.01),and the yolk weight of Linen plumage families 300 day old was significantly higher than that of Yellow plumage families(P<0.05);There was no significant difference in body weight at the brood stage between two populations of Yellow plumage chickens and Linen plumage chickens in one generation core group(P>0.05).The results show that the Yellow plumage families have more advantages in growth performance and the Linen plumage families have better egg laying performance.2.Seven SNP loci were detected in the QDPR gene of Wumeng crested chickens,among which,the g.76000219 T> A on exon 7 was synonymous mutation.In S2 locus of roosters,the bodyweight of FF genotype at 0-week-old was significantly higher than that of EE genotype(P<0.05);In L1 locus of hens,the bodyweight of MN genotype at 16-week-old was significantly higher than that of NN genotype(P<0.05),in the L2 locus of hens,the bodyweight of AG genotype at 0-week-old was significantly higher than that of GG genotype(P<0.05);Diplotypes analysis showed that the double type of H6H6 was beneficial to the weight of roosters,while the double type of H1H5 and H2H4 were beneficial to the weight of hens.3.Three SNP loci were detected in RBP4 A gene of Wumeng crested hens,among which,the g.21357963 A>G on exon 5 was synonymous mutation;Double type analysis showed that the egg shape index of H1H2 double type was significantly higher than that of H2H2 and H2H3 double type(P<0.05),and the birth weight was significantly lower than that of H2H2 and H2H3 double type(P<0.01),indicating that H1H2(CC/AG/AG)double type was the dominant genotype in laying performance of hens.4.The Real-time quantitative PCR detection showed that QDPR gene m RNA was expressed in seven tissues of Wumeng crested chickens.The expression of QDPR gene m RNA was different in different growth stages of roosters and hens.With the increase of time,the tissues of roosters showed an overall "S" type trend,while the hens showed a "U" type trend.The expression of m RNA in visceral tissues of roosters and hens was higher than that in muscle tissues.5.In addition to the heart and kidney,the expression of RBP4 A gene m RNA of Wumeng crested chickens increased first and then decreased with time,this expression peaked at the 35 week peak period of laying,and the difference between the highest and the lowest expression in most tissues was very significant(P<0.01).It was speculated that the RBP4 A gene had a positive regulatory effect on laying performance of Wumeng crested chickens. |
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