ABSTRACT
The objective of this study was to evaluate the effect of intronic single nucleotide polymorphisms (SNP) on temperament traits in a Brahman cattle population. The SNP located in CACNG4, EXOC4, NRXN3, and SLC9A4 candidate genes were genotyped in 250 animals with temperament records of exit velocity, pen score, and temperament score. Rs3423464051:G>A in the CACNG4 gene was associated with exit velocity and temperament score. An in silico analysis of the five intronic SNP showed that alternative alleles of CACNG4-rs3423464051, EXOC4-rs109393235, and SLC9A4-rs109722627 SNP could alter branch point sites during splicing, while a protein–protein interaction network analysis demonstrated a GRIA2 gene-mediated interaction between CACNG4 and NRXN3. The present results support previously reported evidence regarding bovine temperament-related candidate genes, particularly CACNG4, which is a confirmed candidate gene in need of more detailed analyses to reveal its role in temperament-related traits.
beef cattle; behavior; molecular markers
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MP - DNA marker ladder.The figures show the PCR-RFLP results for each marker-genotype assignations.A: For CACNG4-rs3423464051, the GG genotype is characterized by 104, 77, and 61 pb bands; AA genotype is distinguished for the 120 and 77-pb bands.B: In the SLC9A4-rs110864071, the CC genotype displays two bands of 190 and 138-bp, while TT genotype has a differential 235 and 138-pb pattern.C: The SLC9A4-rs109722627 GG genotype has two bands of 189 and 140 pb, while the TT genotype shows a main band of 329.D: The GG genotype of NRXN3- rs135982573 shows a differential band of 316-pb and AA genotype, and has three bands of 182, 134, and 52-pb.In all markers, the heterozygote carriers are characterized by a band pattern combining both homozygotes.
A: Distribution of animals segregated into three temperament classifications and year of birth (black: calm; dark gray: intermediate; light gray: temperamental).B: Mean values of exit velocity (EV), pen score (PS), and temperament score (TS) by year of birth (black: 2018, dark gray: 2019, and light gray: 2020).
Candidate genes linked by a line have a prediction based on physical or functional interaction. The GRIA2 gene mediates the interaction between the NRXN3 and CACNG4 genes. However, the EXOC4 and SLC9A4 genes do not exhibit direct interactions with each other or with other genes.