Acta Veterinaria et Zootechnica Sinica ›› 2022, Vol. 53 ›› Issue (11): 3769-3785.doi: 10.11843/j.issn.0366-6964.2022.11.006

• ANIMAL GENETICS AND BREEDING • Previous Articles     Next Articles

Association Analysis of MET Gene Single Nucleotide Polymorphism with Reproduction and Milk Production Traits in Chinese Holstein Cattle

XU Jingyi1, XU Haoqi1, HU Lirong1, ZHANG Fan2, GAO Qing1, LUO Hanpeng1, ZHANG Hailiang1, SHI Rui1, LI Xiang1, LIU Lin3, GUO Gang4*, WANG Yachun1*   

  1. 1. National Engineering Laboratory for Animal Breeding, Key Laboratory of Animal Genetics, Breeding and Reproductive of Ministry of Agriculture and Rural Affairs, College of Animal Science and Technology, China Agricultural University, Beijing 100193, China;
    2. College of Animal Science, Xinjiang Agricultural University, Urumqi 830052, China;
    3. Beijing Dairy Cattle Center, Beijing 100194, China;
    4. Beijing Sunlon Livestock Development Company Limited, Beijing 100029, China
  • Received:2022-04-11 Online:2022-11-23 Published:2022-11-25

Abstract: In order to identify genetic markers related to reproduction and milk production traits of Chinese Holstein cattle, the relationships between single nucleotide polymorphisms (SNPs) of MET gene and reproduction and milk production traits was explored. Candidate SNPs of MET were screened through direct sequencing of pooled DNA samples in 70 healthy unrelated Chinese Holstein bulls, and the genotyping of partial SNPs in 1 160 healthy Holstein lactating cattle was performed using kompetitive allele-specific PCR (KASP) method, diplotype information based on linkage disequilibrium analysis was obtained. The linear models were employed to conduct the association analysis between SNPs and their diplotypes and EBVs of 5 reproductive traits and 6 milk production traits. The bioinformatics analysis and the association analysis were conducted on SNPs located in functional areas. In this study, a total of 19 SNPs were detected in MET, indicating rich genetic variations existing within this gene in the population. Among them, 7 SNPs was genotyped, and the association analysis revealed that these SNPs were significantly (P<0.05) or highly significantly (P<0.01) associated with multiple traits. The individuals with GG genotype of g.51737889T>C located in upstream had the lowest EBVs of the age at the first calving (AFC), the interval from the first to last insemination in heifer (IFL_H), the interval from the first to last insemination in cows (IFL_C), and somatic cell score (SCS), which suggested the good reproduction and milk production performance of animals carrying this genotype. The individuals with GG genotype of g.51736640A>C located in upstream had the lowest EBVs of the age at the first calving, the interval from the first to last insemination in heifers, the interval from the first to last insemination in cows, and somatic cell score; however, they had the lowest EBVs of protein percentage (PP), and fat percentage (FP), which suggested animals carrying this genotype had the good performance in reproductive, but with relatively poor performance in milk production. The individuals with the TC genotype at g.51660569G>A in 6th exon had the lowest EBVs of the interval from the first to last insemination in heifers and the interval from the first to last insemination in cows, which suggested the good reproduction performance of animals carrying this genotype. Linkage disequilibrium analysis revealed that 7 SNPs linked to form 2 haplotype blocks. The association analysis between diplotypes and target traits showed that the individuals with H1H3 diplotype at BLOCK1 had good reproduction performance but medium milk production performance, the individuals with H4H4 diplotype at BLOCK2 had good reproduction and milk production performance, and these two were dominant hiplotypes. In addition, H1H3 diplotype included the TC genotype at g.51660569G>A, H4H4 diplotype was combination of the GG genotype at g.51737889T>C and g.51736640A>C, the results of diplotype association analysis were consistent with that of SNP. The results of motif analysis showed that G allele at g.51737889T>C and g.51736640A>C enriched in transcription factors related to gene activation, cell proliferation and differentiation. The individuals with GG genotype at both SNPs had the highest gene expression, and the individuals with corresponding H4H4 diplotype had higher gene expression, which further verified the results of association analysis. In conclusion, the polymorphism map of MET gene was derived in Chinese Holstein cattle, and the genetic association between MET gene and reproductive and productive traits was identified through association analysis, and verified by bioinformatics prediction and gene expression analysis. The results provided useful genetic markers for genetic selection of Chinese Holstein cattle for higher production as well as higher efficiency.

Key words: MET, single nucleotide polymorphism, haplotype, gene expression, cow, association analysis

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