Hideyuki Mannen

Genotype of stearoyl-CoA desaturase is associated with fatty acid composition in Japanese Black cattle

To investigate the genetic factors that affect fatty acid composition of beef, we compared the full-length bovine stearoyl-CoA desaturase (SCD) cDNA from 20 Japanese Black steers. Two types of the SCD gene with single nucleotide polymorphisms (SNPs) were observed in the ORF of SCD cDNA, in which an amino acid replacement from valine (type V) to alanine (type A) was predicted. We developed a method for genotyping these two SCD genes based on PCR-RFLP. We have classified 1003 Japanese Black carcasses into three genotypes, VV, VA, and AA, and compared fatty acid composition among them. The SCD type A gene contributed to higher MUFA percentage and lower melting point in intramuscular fat. The SCD genotype was not the only genetic factor contributing to fatty acid composition of Japanese Black steers, but the SCD genotype was considered one of the causes of genetic variation in fatty acid composition of Japanese Black steers. Transcription factors such as sterol regulatory element binding protein-1c (SREBP-1c) may account for the remaining part of the genetic variation in fatty acid composition.

Whole genome linkage disequilibrium maps in cattle

BackgroundBovine whole genome linkage disequilibrium maps were constructed for eight breeds of cattle. These data provide fundamental information concerning bovine genome organization which will allow the design of studies to associate genetic variation with economically important traits and also provides background information concerning the extent of long range linkage disequilibrium in cattle.ResultsLinkage disequilibrium was assessed using r2 among all pairs of syntenic markers within eight breeds of cattle from the Bos taurus and Bos indicus subspecies. Bos taurus breeds included Angus, Charolais, Dutch Black and White Dairy, Holstein, Japanese Black and Limousin while Bos indicus breeds included Brahman and Nelore. Approximately 2670 markers spanning the entire bovine autosomal genome were used to estimate pairwise r2 values. We found that the extent of linkage disequilibrium is no more than 0.5 Mb in these eight breeds of cattle.ConclusionLinkage disequilibrium in cattle has previously been reported to extend several tens of centimorgans. Our results, based on a much larger sample of marker loci and across eight breeds of cattle indicate that in cattle linkage disequilibrium persists over much more limited distances. Our findings suggest that 30,000–50,000 loci will be needed to conduct whole genome association studies in cattle.

Zebu Cattle Are an Exclusive Legacy of the South Asia Neolithic

Animal domestication was a major step forward in human prehistory, contributing to the emergence of more complex societies. At the time of the Neolithic transition, zebu cattle (Bos indicus) were probably the most abundant and important domestic livestock species in Southern Asia. Although archaeological evidence points toward the domestication of zebu cattle within the Indian subcontinent, the exact geographic origins and phylogenetic history of zebu cattle remains uncertain. Here, we report evidence from 844 zebu mitochondrial DNA (mtDNA) sequences surveyed from 19 Asiatic countries comprising 8 regional groups, which identify 2 distinct mitochondrial haplogroups, termed I1 and I2. The marked increase in nucleotide diversity (P < 0.001) for both the I1 and I2 haplogroups within the northern part of the Indian subcontinent is consistent with an origin for all domestic zebu in this area. For haplogroup I1, genetic diversity was highest within the Indus Valley among the three hypothesized domestication centers (Indus Valley, Ganges, and South India). These data support the Indus Valley as the most likely center of origin for the I1 haplogroup and a primary center of zebu domestication. However, for the I2 haplogroup, a complex pattern of diversity is detected, preventing the unambiguous pinpointing of the exact place of origin for this zebu maternal lineage. Our findings are discussed with respect to the archaeological record for zebu domestication within the Indian subcontinent.

Genotype of bovine sterol regulatory element binding protein-1 (SREBP-1) is associated with fatty acid composition in Japanese Black cattle

To investigate genetic factors that affect fatty acid composition in beef carcass, we previously investigated genetic profiles of stearoyl-CoA desaturase (SCD) and their effect on fatty acid composition in fat tissue of cattle. It has been known that sterol regulatory element binding protein (SREBP) is a transcription factor that regulates gene expression levels of SCD and other genes relevant to lipid and fatty acid metabolism in tissue. Therefore, we determined the full-length sequence of bovine SREBP-1 cDNA and then surveyed polymorphisms in whole exons and introns in the bovine genome. Large 84-bp insertion (long type: L) and deletion (short type: S) were found in intron 5 of bovine SREBP-1 in Japanese Black cattle, although there was no notable mutation in exon regions. The associations between the SREBP-1 genotypes and fatty acid compositions/fat melting points were analyzed by using genomic DNA with carcass trait information from 606 Japanese Black cattle. The S type contributed to 1.3% higher monounsaturated fatty acid (MUFA) proportion and 1.6°C lower melting point in intramuscular fat. Genotyping of bovine SREBP-1 is considered to reflect a genetic variation which is associated with physiologic characteristics of fat tissue in Japanese black cattle.

An assessment of population structure in eight breeds of cattle using a whole genome SNP panel

BackgroundAnalyses of population structure and breed diversity have provided insight into the origin and evolution of cattle. Previously, these studies have used a low density of microsatellite markers, however, with the large number of single nucleotide polymorphism markers that are now available, it is possible to perform genome wide population genetic analyses in cattle. In this study, we used a high-density panel of SNP markers to examine population structure and diversity among eight cattle breeds sampled from Bos indicus and Bos taurus.ResultsTwo thousand six hundred and forty one single nucleotide polymorphisms (SNPs) spanning all of the bovine autosomal genome were genotyped in Angus, Brahman, Charolais, Dutch Black and White Dairy, Holstein, Japanese Black, Limousin and Nelore cattle. Population structure was examined using the linkage model in the program STRUCTURE and Fst estimates were used to construct a neighbor-joining tree to represent the phylogenetic relationship among these breeds.ConclusionThe whole-genome SNP panel identified several levels of population substructure in the set of examined cattle breeds. The greatest level of genetic differentiation was detected between the Bos taurus and Bos indicus breeds. When the Bos indicus breeds were excluded from the analysis, genetic differences among beef versus dairy and European versus Asian breeds were detected among the Bos taurus breeds. Exploration of the number of SNP loci required to differentiate between breeds showed that for 100 SNP loci, individuals could only be correctly clustered into breeds 50% of the time, thus a large number of SNP markers are required to replace the 30 microsatellite markers that are currently commonly used in genetic diversity studies.

Effects of bovine fatty acid synthase, stearoyl-coenzyme A desaturase, sterol regulatory element-binding protein 1, and growth hormone gene polymorphisms on fatty acid composition and carcass traits in Japanese Black cattle

The quality of fat is an important factor in defining the quality of meat. Fat quality is determined by the composition of fatty acids. Among lipid metabolism-related genes, including fatty acid synthesis genes, several genetic variations have been reported in the bovine fatty acid synthase (FASN), stearoyl-CoA desaturase (SCD), sterol regulatory element-binding protein 1 (SREBP1), and GH genes. In the present study, we evaluated the single and epistatic effects of 5 genetic variations (4 SNP and 1 insertion/deletion) in 4 genes (FASN, SCD, SREBP1, and GH) on the fatty acid composition of the longissimus thoracis muscle and carcass and meat quality traits in 480 commercial Japanese Black cattle. Significant single effects of FASN, SCD, and GH(L127V) polymorphisms on the fatty acid composition of the longissimus thoracis muscle were detected. The A293V polymorphism of SCD had the largest effect on myristic acid (C14:0, P < 0.001), myristoleic acid (C14:1, P < 0.001), stearic acid (C18:0, P < 0.001), oleic acid (C18:1, P < 0.001), and MUFA (P < 0.001). Polymorphisms in the FASN, SCD, and SREBP1 genes showed no effect on any meat yield trait. There were no significant epistatic effects on fatty acid composition among pairs of the 3 genes (FASN, SCD, and SREBP1) involved in fatty acid synthesis. No epistatic interactions (P > 0.1) were detected between FASN and SCD for any carcass trait. When the genotypes of 3 markers (FASN, SCD, and GH(L127V)) were substituted from the lesser effect allele to the greater effect allele, the proportion of C18:1 increased by 4.46%. More than 20% of the genetic variance in the C18:1 level could be accounted for by these 3 genetic markers. The present results revealed that polymorphisms in 2 fatty acid synthesis genes (FASN and SCD) independently influenced fatty acid composition in the longissimus thoracis muscle. These results suggest that SNP in the FASN and SCD genes are useful markers for the improvement of fatty acid composition in commercial Japanese Black cattle.

Association between fatty acid compositions and genotypes of FABP4 and LXR-alpha in Japanese Black cattle

BackgroundFatty 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 α (LXRα), cytochrome b5 (Cyt b5), long-chain acyl-CoA synthetase (ACSL) 1, ACSL4 and diacylglycerol acyltransferase 2 (DGAT2) and fatty acid composition.ResultsSequence comparisons revealed 14 single nucleotide polymorphisms in six genes. Four of them, I74V and V110M in FABP4 and G51E and V133I in LXRα, 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 LXRα 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.ConclusionOur findings suggest that the two polymorphisms of FABP4 I74V and LXRα V133I might be genetic factors in part associated with palmitoleic acid (FABP4 I74V) and linoleic acid (LXRα 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.

Mitochondrial DNA reveal that domestic goat (Capra hircus) are genetically affected by two subspecies of bezoar (Capra aegagurus).

This article describes the complete sequences of the mitochondrial DNA displacement loop (D-loop) region and cytochrome b gene from domestic goats in Laos (Laos native) and wild goat “markhor” (C. falconeri). The wild goat “bezoar” (Capra aegagrus) has been considered to be the strongest candidate for the ancestor of the domestic goats (C. hircus); however, there is not sufficient molecular data to verify the hypothesis at present. In phylogenetic analyses, two wild goats, the markhor and the ibex (C. ibex), appeared as an outgroup, while the bezoar was located in a cluster of domestic goats. Mitochondrial haplotypes of Laos natives revealed two distinct major clusters: one was the same as the bezoar, the second, unique to Laos natives. The topology and calibrated levels of sequence divergence suggests that these clusters might represent at least two different subspecies of ancestral bezoars.

Effect of SCD and SREBP genotypes on fatty acid composition in adipose tissue of Japanese Black cattle herds.

Fatty acid composition of beef adipose tissue is one of important traits because high proportions of monounsaturated fatty acid are related to favorable beef flavor and tenderness. In this study, we investigated effects of genetic factors such as stearoyl-CoA desaturase (SCD) and sterol regulatory element binding protein (SREBP) on beef carcass traits including fatty acid composition using two cattle populations. Sire effect was significantly related to almost all traits except BMS, suggesting that the trait examined in this study is highly controlled by genetic factors. The effect of SCD genotype on fatty acid composition was detected remarkably in both cattle groups, especially on stearic and oleic acids. This result was consistent with our previous studies and suggests that SCD is associated with fatty acid composition. Unlike SCD genotyping, the effect of SREBP genotype was not identified in this study. Our results suggested that SCD genotype would contribute to improving beef quality in field populations. Further studies about the relationship among these factors will bring an insight into the molecular mechanism of fatty acid metabolism in cattle.

Development of breed identification markers derived from AFLP in beef cattle

In the meat industry, correct breed information in food labeling is required to assure meat quality. Genetic markers provide corroborating evidence to identify breed. This paper describes the development of DNA markers to discriminate between Japanese Black and F1 (Japanese Black×Holstein) breeds. Amplified fragment length polymorphism method was employed to detect candidate markers absent in Japanese Black but present in Holstein. The 500 primer combinations yielded six selected markers that were converted into single nucleotide polymorphisms markers for high-throughput genotyping. The allele frequencies in both breeds were investigated for discrimination ability using PCR-RFLP. The probability of identifying F1 was 0.882 and probability of misjudgment was 0.0198. The markers could be useful for discriminating between Japanese Black and F1 and would contribute to the elimination of falsified breed labeling of meat.