Copy number variation of EIF4A2 loci related to phenotypic traits in Chinese cattle

Background: Generally, copy number variation (CNV) is a large-scale structural variation between 50 bp and 1 kb of the genome. It can affect gene expression and is an important reason for genetic diversity and phenotypic trait diversity. Studies have shown that the eukaryotic translation initiation factor 4A2 (EIF4A2) gene plays an essential role in muscle development in both humans and pigs. However, the influence of bovine EIF4A2's copy number change on phenotypic traits has not been reported. Objectives: To detect the tissue expression profile of the EIF4A2 gene in adult cattle and individuals' CNV type of variation. Then, we explored the correlation between EIF4A2-CNV and growth traits in Chinese cattle breeds. Methods: Real-time fluorescent quantitative reverse transcription PCR (qRT-qPCR) was used to determine the expression profile of the EIF4A2 gene. Real-time fluorescent quantitative PCR (q PCR) was used to detect the CNV type of bovine populations. Then, SPSS 26.0 was used for association analysis. Results: In this study, a total of 513 individuals in four cattle breeds (Qinchuan cattle [QC], Yunling cattle [YL], Pinan cattle [PN] and Jiaxian cattle [JX]) were detected for EIF4A2 gene's CNV. The results showed that EIF4A2-CNV has an essential impact on hip width (HW) and rump length (RL) in QC, heart girth (HG), chest depth (CD) and RL in YL and HW in PN. However, it had no significant effect on JX. Conclusions: The above results suggest that EIF4A2 gene's CNV can be used as a molecular marker for cattle breeding, which is helpful to accelerate the breeding of superior beef cattle breeds.