Identification of Genetic Markers of <i>APOM</i> and <i>CYP7A1</i> Genes Affecting Milk Production Traits in Chinese Holstein
Our previous study identified the apolipoprotein M (<i>APOM</i>) and cytochrome P450 family 7 subfamily A polypeptide 1 (<i>CYP7A1</i>) genes as candidates for milk traits in dairy cattle, which were significantly up-regulated in liver tissue of Holstein cows between the dry...
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| Main Authors: | , , , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2024-12-01
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| Series: | Agriculture |
| Subjects: | |
| Online Access: | https://www.mdpi.com/2077-0472/15/1/33 |
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| Summary: | Our previous study identified the apolipoprotein M (<i>APOM</i>) and cytochrome P450 family 7 subfamily A polypeptide 1 (<i>CYP7A1</i>) genes as candidates for milk traits in dairy cattle, which were significantly up-regulated in liver tissue of Holstein cows between the dry and lactation periods. The two genes play critical roles in the peroxisome proliferator-activated receptor (PPAR) pathway. In this study, we further confirmed whether the <i>APOM</i> and <i>CYP7A1</i> genes had significant genetic impacts on milk production traits in a Chinese Holstein population. By dual-direction sequencing of the polymerase chain reaction (PCR) products of the complete coding sequences and 2000 bp of the 5′ and 3′ flanking regions on pooled DNA sample, seven and three single nucleotide polymorphisms (SNPs) were identified in <i>APOM</i> and <i>CYP7A1</i>, respectively. With SAS 9.2, phenotype-genotype association analysis revealed such SNPs were significantly associated with at least one of the milk production traits, including 305-day milk yield, milk fat yield, milk fat percentage, milk protein yield, and milk protein percentage in the first and second lactations (<i>p</i> = <0.01~0.04). With Haploview 4.2, we further found that six SNPs in <i>APOM</i> and thee SNPs in <i>CYP7A1</i> formed one haplotype, respectively. The haplotypes were significantly associated with at least one of milk production traits as well (<i>p</i> = <0.01~0.02). Of note, we found the SNPs in the 5′ regulatory region, rs209293266 and rs110721287 in <i>APOM</i> and rs42765359 in <i>CYP7A1</i>, significantly impacted the gene transcriptional activity after mutation (<i>p</i> < 0.01) through changing the transcription factor binding sites by using luciferase assay experiments. Additionally, with RNAfold Web Server, rs110098953 and rs378530166 changed the mRNA secondary structures of <i>APOM</i> and <i>CYP7A1</i> genes, respectively. In summary, our research is the first to demonstrate that <i>APOM</i> and <i>CYP7A1</i> genes have significantly genetic effects on milk yield and composition traits, and the identified SNPs may serve as available genetic markers for genomic selection program in dairy cattle. |
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| ISSN: | 2077-0472 |