| Lueyang black chicken is a famous local breed in China.Its egg is rich in nutrition and has medicinal and health functions.However,the egg production performance of Lueyang black chicken is poor(85-115 eggs / year),which significantly increases the production cost of black chicken breeding and commercial eggs,and has a very negative impact on the development of black chicken industry.In this study,we estimated the genetic parameters of laying number and analyzed the relationship between AMH and laying performance,in order to find out the genetic basis of laying performance and provide theoretical basis for breeding laying performance.The body weight at 6,10,14,20 weeks and the number of eggs at 31,35 and 40 weeks of age of 1600 individuals of one generation in the breeding core group of Lueyang black egg line were measured.The heritability of each trait and the genetic correlation among the traits were estimated by Bayesian algorithm.The results showed that: 1.The egg laying performance of Lueyang black chicken population was low,and the traits showed great differences in the population,the coefficient of variation was between 36.8% and 39.2%;2.The heritability of the egg laying traits of Lueyang black chicken was low(0.25-0.27),but there was a strong genetic correlation among the egg laying traits of the three periods,the genetic correlation coefficient was close to 1;3.The egg laying traits of each period There was a negative genetic correlation between C and birth weight,but the confidence interval of all negative genetic correlation estimates was across 0,so the negative genetic correlation was not statistically significant.On the basis of elucidating the genetic characteristics of the population,we studied the expression of AMH gene related to follicular development and the relationship between AMH sequence variation and egg production of Lueyang black chicken.Firstly,the expression of AMH gene in the pre follicle of different egg laying individuals was detected by fluorescence quantitative PCR.Second,using cluster Omega online multiple sequence alignment program(https://www.ebi.ac.uk/tools/msa/clustalo/)and homology modeling were used to analyze the conservation of avian and mammalian AMH proteins and variation sites(Val566Ile),to establish the three-dimensional structure of wild and variant AMH proteins,and to detect the effect of variation on protein structure.Finally,Val was analyzed by TDT model based on orthogonal family The correlation between 566 ile and egg number.The results showed that: 1.There was no significant difference in AMH expression between high-yield Nick chicken and low-yield Lueyang black chicken(P > 0.05).2.In general,the amino acid homology of chicken AMH protein and mammalian amino acid is low,but the C-terminal with biological activity keeps high conservation,while the heterotopic point in animals other than Turkey is not conservative,and its hydrophobicity is completely conservative;3.According to the simulation of three-dimensional structure,val566 ile The mutation affected the hydrogen bond and water solubility of several amino acid residues and added a new ? helix.4.There was no significant correlation between the number of eggs laid at 31,35 and 40 weeks old and the genotype of Lueyang black chicken(P > 0.05).The results showed that the heritability of laying number of Lueyang black chicken was low,and it was difficult to breed directly.The positive genetic correlation between the number of laying eggs at different time points indicates that it is feasible to select early laying eggs according to the age of 31 weeks.The weight and the number of eggs kept a relatively independent genetic relationship,indicating that the breeding of the two characters could be improved at the same time.In the study of AMH candidate gene expression and variation,we found that val566 ile had an effect on the protein highlevel structure,but there was no significant correlation between the expression of val566 ile and AMH and egg laying traits in statistics,indicating that the expression of val566 ile and AMH may not be an important genetic factor affecting egg laying of Lueyang black chicken,which laid a foundation for molecular breeding of egg laying of Lueyang black chicken. |
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