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Background: Beef marbling is considered a desirable trait in the meat industry. Therefore, understanding the genetic factors that cause marbling is important. Previously, we performed a genome-wide association study to examine genetic factors associated with beef marbling in Japanese Black cattle and identified a candidate region between 10-30 Mbp on chromosome 7. We verified the effect of the SNPs in this region on beef marbling using linkage disequilibrium block analysis. We narrowed down the candidate region to a range of 15.8-16.1 Mbp. In this study, we comprehensively detected all of the SNPs in this region and verified their effects on beef marbling., Results: Genome resequencing using four animals exhibiting high beef marbling standard (BMS) and four with low BMS revealed a total of 1,846 polymorphisms within the candidate region. Based on the annotation, we selected 13 SNPs exhibiting a moderate impact, as no high-impact SNPs were detected. All of the SNPs represented missense polymorphisms and were located in the following seven genes: RDH8, ANGPTL6, DNMT1, MRPL4, ICAM1, ICAM3, and ICAM5. Finally, we determined the effects of these SNPs on the BMS of a Japanese Black cattle population (n = 529). Analysis of variance revealed that the five SNPs were located in genes encoding the intercellular adhesion molecules (ICAM1, ICAM3, and ICAM5), and showed a highly significant association compared with the remainder (p < 0.01). The lowest p-value was observed for ICAM3&#95;c.739G > A (p = 1.18E-04). Previous studies have suggested that intercellular adhesion molecules (ICAM) may be an upstream factor that regulates adipocyte differentiation. Therefore, considering the polymorphism and putative gene function, we suggest that ICAM1 is potentially responsible for beef marbling. c.470C > G and/or c.994G > A on ICAM1 may be responsible for this quantitative trait locus., Conclusions: Promising SNP candidates responsible for beef marbling were identified using extensive polymorphism verification in a previously reported QTL region. We aim to elucidate the mechanism of beef marbling in future studies by investigating how these polymorphisms alter protein structure and function., (© 2024. The Author(s).)

Background: Fatty acid composition has become an important trait in the beef industry in terms of beef flavor and decreasing the circulating concentration of LDL cholesterol. In this study, we examined the association between polymorphisms of six genes, adipocytes-type fatty acid binding protein (FABP4), liver X receptor alpha (LXRalpha), cytochrome b5 (Cyt b5), long-chain acyl-CoA synthetase (ACSL) 1, ACSL4 and diacylglycerol acyltransferase 2 (DGAT2) and fatty acid composition., Results: Sequence comparisons revealed 14 single nucleotide polymorphisms in six genes. Four of them, I74V and V110M in FABP4 and G51E and V133I in LXRalpha, were nonsynonymous substitutions. The associations between the genotypes and fatty acid compositions were analyzed by using 234 Japanese Black cattle. The genotypes of FABP4 I74V and LXRalpha V133I were significantly associated with palmitoleic acids (C16:1, P = 0.0086) and linoleic acid (C18:2, P = 0.0121) content in intramuscular fat, respectively., Conclusion: Our findings suggest that the two polymorphisms of FABP4 I74V and LXRalpha V133I might be genetic factors in part associated with palmitoleic acid (FABP4 I74V) and linoleic acid (LXRalpha V133I) composition in intramuscular fat of Japanese Black cattle, respectively. Especially, FABP4 I74V had highly significant effect (P < 0.01) on C16:1 proportion, indicating that the I/I homozygote exhibited 0.5% higher percentage than V/V homozygote.