Two single nucleotide polymorphisms sites in \u03b11-AT gene and their association with somatic cell score in Chinese Holstein cows

Xiao-Fei Guo,Ran Di,Qiu-Ling Li,Yong-Fu An,Ming-Xing Chu,Xian-Zheng Lang,Xiang-Yu Wang,Qiu-Yue Liu,Wen-Ping Hu,Xiao-Lin Liu

doi:10.1186/s40709-017-0065-z

Abstract

BackgroundAlpha 1-antitrypsin (α1-AT) may affect the susceptibility of mastitis in dairy cattle for its possible role in the protection of lactoferrin from proteolytic degradation in the mammary. Milk somatic cell score (SCS) is a logarithmic transformation of the milk somatic cell count widely used as an index to evaluate mastitis. To study the relationships of α1-AT gene and SCS in Chinese Holstein cows, methods of PCR-SSCP, DNA sequencing, PCR-RFLP, and CRS-PCR technologies were used to detect single nucleotide polymorphisms sites in α1-AT gene.ResultsTwo polymorphic sites at G5503A and G5746C of α1-AT gene were found. AA (0.3633), AB (0.4644) and BB (0.1723) genotypes were detected at G5503A site, CC (0.3483), CD (0.4906) and DD (0.1611) genotypes were found at G5746C in Chinese Holstein cows. Least squares mean of SCS for individuals with BB genotype was significantly lower than that with AA and AB genotype (p < 0.01), and that with AB genotype was significantly lower than that with AA (p < 0.05). There was no significant difference among individuals with CC, CD and DD genotypes (p > 0.05). Least squares mean of SCS for individuals with BBDD genotype combination were significantly lower than those with AACC and AACD (p < 0.05).ConclusionsStatistical analysis indicated that B allele and BBDD genotype combination of α1-AT can improve mastitis resistance in dairy cattle.

Highlights

Alpha 1-antitrypsin (α1-AT) may affect the susceptibility of mastitis in dairy cattle for its possible role in the protection of lactoferrin from proteolytic degradation in the mammary
The results preliminarily indicated that allele B of G5503A polymorphic site of alpha 1-antitrypsin (α1-AT) gene is a potential DNA marker for improving mastitis resistance in Chinese Holstein cow
The two mutations in this study caused no amino acid change, similar to Conclusions The relationship between the two single nucleotide polymorphisms sites of α1-AT gene and somatic cell count (SCC)/somatic cell score (SCS) in Chinese Holstein cow milk was explored in the present study

Summary

Introduction

Alpha 1-antitrypsin (α1-AT) may affect the susceptibility of mastitis in dairy cattle for its possible role in the protection of lactoferrin from proteolytic degradation in the mammary. To study the relationships of α1-AT gene and SCS in Chinese Holstein cows, methods of PCR-SSCP, DNA sequencing, PCR-RFLP, and CRS-PCR technologies were used to detect single nucleotide polymorphisms sites in α1-AT gene. Five single nucleotide polymorphisms (SNPs) in coding regions of the bovine α1-AT gene were found by direct sequencing of reverse transcription-polymerase chain reaction (RT-PCR) products from a wide range of cattle tissues. The relationship of these SNPs with the economic traits in North American Holstein population was studied [9]. Researchers had reported that α1-AT gene was associated with milk production traits in dairy cattle [10,11,12]

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Conclusion