記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：BIOMED CENTRAL LTD  

Background: Conception is a fundamental trait for successful cattle reproduction. However, conception rates in Japanese Black cattle have been gradually declining over the last two decades. Although conception failures are mainly caused by embryonic mortality, the role of maternal genetic factors in the process remains unknown. Copy number variation (CNV), defined as large-scale genomic structural variants, contributes to several genetic disorders. To identify CNV associated with embryonic mortality in Japanese Black cattle, we evaluated embryonic mortality as a categorical trait with a threshold model and conducted a genome-wide CNV association study for embryonic mortality using 791 animals.Results: We identified a deleted-type CNV ranging from 378,127 to 412,061 bp on bovine chromosome 8, which was associated with embryonic mortality at 30-60 days after artificial insemination (AI). The CNV harbors exon 2 to 6 of ANNEXIN A10 (ANXA10). Analysis of sequence traces from the CNV identified that 63 bp reads bridging the breakpoint were present on both sides of the CNV, indicating that the CNV was generated by non-allelic homologous recombination using the 63 bp homologous sequences. Western blot analysis showed that the CNV results in a null allele of ANXA10. This association was replicated using a sample population size of 2552 animals. To elucidate the function of ANXA10 in vivo, we generated Anxa10 null mice using the CRISPR/Cas9 system. Crossbreeding experiments showed that litter size from crosses of both Anxa10(-/-) and Anxa10(+/-) females had fewer pups than did Anxa10(+/+) females, and embryos of Anxa10(-/-) females died between implantation stages E4.5 and E12.5. These results indicate that loss of maternal Anxa10 causes embryonic mortality.Conclusions: This study identified a deleted-type CNV encompassing ANXA10 in cows that was associated with embryonic mortality at 30-60 days after AI. Using a mouse model, we confirmed that litter sizes were smaller in crosses of both Anxa10(-/-) and Anxa10(+/-) females relative to those of wild females. These results indicate that ANXA10 is a maternal factor that is critical for embryo development.

DOI： 10.1186/s12864-016-3312-z

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：WILEY  

Marker-assisted selection (MAS) is expected to accelerate the genetic improvement of Japanese Black cattle. However, verification of the effects of the genes for MAS in different subpopulations is required prior to the application of MAS. In this study, we investigated the allelic frequencies and genotypic effects for carcass traits of six genes, which can be used in MAS, in eight local subpopulations. These genes are SCD, FASN and SREBP1, which are associated with the fatty acid composition of meat, and NCAPG, MC1R and F11, which are associated with carcass weight, coat color and blood coagulation abnormality, respectively. The frequencies of desirable alleles of SCD and FASN were relatively high and that of NCAPG was relatively low, and NCAPG was significantly associated with several carcass traits, including carcass weight. The proportions of genotypic variance explained by NCAPG to phenotypic variance were 4.83 for carcass weight. We thus confirmed that NCAPG is a useful marker for selection of carcass traits in these subpopulations. In addition, we found that the desirable alleles of six genes showed no negative effects on carcass traits. Therefore, selection using these genes to improve target traits should not have negative impacts on carcass traits.

DOI： 10.1111/asj.12453

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：WILEY-BLACKWELL  

Days open (DO), which is the interval from calving to conception, is an important trait related to reproductive performance in cattle. To identify quantitative trait loci for DO in Japanese Black cattle, we conducted a genome-wide association study with 33303 single nucleotide polymorphisms (SNPs) using 459 animals with extreme DO values selected from a larger group of 15488 animals. We identified a SNP on bovine chromosome 2 (BTA2) that was associated with DO. After imputation using phased haplotype data inferred from 586812 SNPs of 1041 Japanese Black cattle, six SNPs associated with DO were located in an 8.5-kb region of high linkage disequilibrium on BTA2. These SNPs were located on the telomeric side at a distance of 177kb from the parathyroid hormone 2 receptor (PTH2R) gene. The association was replicated in a sample of 1778 animals. In the replicated population, the frequency of the reduced-DO allele (Q) was 0.63, and it accounted for 1.72% of the total genetic variance. The effect of a Q-to-q allele substitution on DO was a decrease of 3.74days. The results suggest that the Q allele could serve as a marker in Japanese Black cattle to select animals with superior DO performance.

DOI： 10.1111/age.12360

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：BMC  

Background: Female fertility, a fundamental trait required for animal reproduction, has gradually declined in the last 2 decades in Japanese Black cattle. To identify associated genetic variants in Japanese Black cattle, we evaluated female fertility as a metric to describe the average inverse of the number of artificial inseminations required for conception from the first through the fourth parity (ANAI(4)) and conducted a genome-wide association study (GWAS) using 430 animals with extreme ANAI(4) values from 10,399 animals.Results: We found that 2 variants, namely a single-nucleotide polymorphisms (SNP; g.48476925C > T) and a 3-bp indel (g.48476943_48476946insGGC), in the upstream region of the activin receptor IIA gene (ACVR2A) were associated with ANAI(4). ACVR2A transcripts from Japanese Black cattle of the Q haplotype, defined by the SNP and the 3-bp indel, with increased ANAI(4) were 1.29-1.32-fold more abundant than q-derived transcripts. In agreement, reporter assay results revealed that the activity of the ACVR2A promoter was higher in reporter constructs with the Q haplotype than in those with the q haplotype by approximately 1.2 fold. Expression of exogenous ACVR2A induced dose-dependent increases of reporter activity from the follicle-stimulating hormone, beta polypeptide (FSHB) promoter in response to activin A in a pituitary gonadotrophic cell line. The findings suggested that sequence variations in the upstream region of ACVR2A with the Q haplotype increased ACVR2A transcription, which in turn induced FSHB expression. This association was replicated using a sample population size of 1,433 animals; the frequency of the Q haplotype was 0.39, and Q-to-q haplotype substitution resulted in an increase of 0.02 in terms of ANAI(4).Conclusions: This GWAS identified variants in the upstream region of ACVR2A, which were associated with female fertility in Japanese Black cattle. The variants affected the level of ACVR2A mRNA expression, which could lead to an allelic imbalance. This association was replicated with a sample population of 1,433 animals. Thus, the results suggest that the Q haplotype could serve as a useful marker to select Japanese Black cattle with superior female fertility.

DOI： 10.1186/s12863-015-0282-0

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：WILEY-BLACKWELL  

Postnatal mortality (PM) of calves is an economically important trait, because a high mortality rate of calves decreases farm income and significantly increases production costs. In spite of the economic importance of PM, genetic studies on PM have been scarce for Japanese Black cattle. The objectives of this study were to estimate the direct and maternal heritability for PM using a Bayesian threshold model with Gibbs sampling in Japanese Black cattle. The original data consisted of 43723 records of animals born from January 2005 to June 2006. Four binary traits of mortality were considered: D1-14, D15-60, D61-180 and D1-180 with numbers indicating the period of risk in days after birth. Direct heritabilities for PM ranged from 0.12 to 0.31 and maternal heritabilities for PM were lower than the direct heritabilities and ranged from 0.02 to 0.16. Direct genetic correlations between D1-14 and D15-60, between D15-60 and D61-180, and between D1-14 and D61-180 were 0.501, 0.689 and 0.062, respectively. Direct genetic correlations of birth weight with D1-14, D15-60, D61-180 and D1-180 were 0.089, 0.482, 0.434 and 0.394, respectively. These results indicated that different genes were responsible for early and late PM and early PM (D1-14) can be genetically reduced without influencing birth weight.

DOI： 10.1111/asj.12233

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：WILEY  

Age at first calving (AFC) is an important trait for achieving earlier reproductive performance in cattle. To identify quantitative trait loci for AFC in Japanese Black cattle, we conducted a genome-wide association study using 866 animals with extreme AFC values selected from a larger group of 52009 animals. We identified single nucleotide polymorphisms (SNPs) on bovine chromosome 2 that were associated with AFC. These SNPs were located within 112.8-kbp intronic region of delta/notch-like EGF repeat containing (DNER) and proved to be in a state of high linkage disequilibrium. The association was replicated in an independent sample of 2963 animals. In the replicated population, the frequency of the reduced AFC allele (Q) was 0.463, and the allele accounts for 8% of the total genetic variance. The effect of allele substitution on AFC was a decrease of 11.54days. The results suggest that the Q allele could serve as a useful marker in Japanese Black cattle to select animals with superior AFC performance.

DOI： 10.1111/age.12109

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：WILEY-BLACKWELL  

DOI： 10.1111/asj.12108

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：WILEY  

Japanese Black cattle are at risk for genetic homogeneity due to intensive use of a few sires. Therefore, assessment of the actual genetic diversity of this breed is important for future breeding plans. In the present study, we investigated the genetic diversity within and among eight subpopulations of Japanese Black cattle using 52 microsatellite markers. The parameters for genetic diversity of Japanese Black cattle were comparable to those of other cattle breeds, suggesting that the relatively high genetic diversity of the breed. However, upon comparison among the eight subpopulations, the Hyogo subpopulation showed markedly low genetic diversity. The results of the pairwise F-ST values, phylogenetic network and structure analysis indicated that the Hyogo population has remarkably high level of genetic differentiation from other populations, while Yamagata, Niigata, Hiroshima and Kagawa populations have low levels of genetic differentiation. Furthermore, multidimensional scaling plots indicated that individuals in some subpopulations were separated from individuals in the other subpopulations. We conclude that while the overall genetic diversity of Japanese Black cattle is still maintained at a relatively high level, that of a particular subpopulation is significantly reduced, and therefore the effective population size of the breed needs to be controlled by correct mating strategies.

DOI： 10.1111/asj.12045

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：BIOMED CENTRAL LTD  

Background: Calving efficiency can be described as the measure of a cow's ability to produce viable offspring within a specific period of time. This trait is crucial in beef cattle because calves are necessary both for the production of beef and for heifer replacements. Recently, the number of calves produced at 4 years of age (NCP4) has been used to evaluate the calving efficiency of Japanese Black cattle. To identify variants associated with calving efficiency in Japanese Black cattle, we conducted a genome-wide association study (GWAS) using 688 animals with extreme NCP4 values selected from 15,225 animals.Results: We identified genetic variants on bovine chromosome 12 (BTA12) that were associated with NCP4. The General Transcription Factor IIF, polypeptide 2 (GTF2F2), located in the 132 kbp-associated region, proved to be in strong linkage disequilibrium. We found 15 associated variants in the promoter and the 3' UTR regions. Consistent with this finding, transcripts of GTF2F2 derived from the haplotype (Q) with the increased number of calves were 1.33-fold more abundant than q-derived transcripts. Furthermore, luciferase assays revealed that the activity of the 3' UTR, a region that includes nine SNPs, was higher in constructs with the Q haplotype than in those with the q haplotype by approximately 1.35-fold. In contrast, the activity of the promoter region did not differ between haplotypes. The association was replicated in an independent sample of 827 animals that were randomly selected from the remainder of the cohort from the same farms used in the GWAS. In the replicated population, the frequency of the Q haplotype is 0.313, and this haplotype accounts for 2.69% of the total phenotypic variance. The effect of the Q to q haplotype substitution on NCP4 was 0.054 calves. These findings suggest that variants in the 3' UTR of GTF2F2 affect the level of GTF2F2 mRNA, which is associated with calving efficiency.Conclusions: This GWAS has identified variants in the 3' UTR of GTF2F2 that were associated with the NCP4 of Japanese Black cattle, and this association was validated in an independent sample. The Q haplotype will be immediately useful in improving the calving efficiency of Japanese Black cattle.

DOI： 10.1186/1471-2156-14-41

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：WILEY-BLACKWELL  

Estimates of genetic parameters were obtained for body measurement traits of 648 animals at 4 months of age, of 545 at 8 months and carcass traits of 14972 animals with the use of an animal model by the restricted maximum likelihood procedure. The estimated heritabilities for carcass traits were high (0.41 to 0.54). At 4 months the estimated direct heritabilities for body measurement traits were moderate to high (0.28 to 0.64), except for chest width (0.19); at 8 months they were also moderate to high (0.23 to 0.49), except for chest depth and chest width (0.18 and 0.06, respectively). Maternal heritabilities for all body measurement traits were low at both ages. The results indicate that because of their moderate direct genetic correlations with body measurement traits, carcass weight, rib thickness and subcutaneous fat thickness can be improved; however, rib eye area and beef marbling standard show little such possibility considering their correlation with body measurement traits.

DOI： 10.1111/asj.12005

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：WILEY  

This study was conducted to evaluate the importance of maternal effect on body measurement traits at an early stage of growth, and to estimate the genetic relationships between direct and maternal effects and among body measurement traits at 0 month (0-mo) and 4 months (4-mo) of age in a population of Japanese Black calves. Body measurements and body weight of 889 Japanese Black calves were estimated with the use of an animal model by the Residual Maximum Likelihood procedure. Direct heritabilities were low to moderate, ranging between 0.17 +/- 0.09 and 0.48 +/- 0.13 at 0-mo, and slightly lower, ranging between 0.15 +/- 0.07 and 0.33 +/- 0.13 at 4-mo. Estimated maternal heritabilities were low to moderate, ranging between 0.08 +/- 0.07 and 0.33 +/- 0.07 at 0-mo and 0.13 +/- 0.06 to 0.33 +/- 0.06 at 4-mo. The direct genetic correlations between 0-mo and 4-mo were moderate to highly positive, ranging from 0.53 +/- 0.23 to 0.96 +/- 0.09. The estimated direct genetic correlation of chest width with other width traits was low and positive at both ages, whereas with hip width it was high and positive (0.80 +/- 0.09) at 0-mo, suggesting that simultaneous improvement of body width of the front and back parts is possible. Maternal genetic effects were relatively independent of direct genetic effects for body measurement traits and can be considered in genetic evaluation.

DOI： 10.1111/j.1740-0929.2011.00936.x

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記述言語：英語   出版者・発行元：Cambridge University Press  

The objective of the present study was to determine the optimal culling strategy in relation to biological and economic efficiency (BE and EE, respectively) and annualized net revenue (AN) in the Japanese Black cow–calf production system with special reference to the beef quality of culled cows. The herd model focused on two ways of mating: one-mating trial system (ONE) and continuous-mating trial system (CON). ONE assumed that heifers that fail to conceive are culled and cows that fail to conceive are culled at weaning of their calves, while CON assumed that mating continues until all females theoretically conceive. Least square means of carcass data of Japanese Black cows collected from a cooperative farm in Japan were used to estimate the carcass price of a cow by parity and Beef Marbling Standard (BMS) number. The simulation, assuming the current production situation in Japan, indicated that sales of culled cows accounted for 0·10–0·20 of total sales and was an important element in total production. Comparisons between ONE and CON showed that production efficiency in the current situation is higher in CON. The BE, EE and AN were higher in CON than in ONE. The two economic indicators were less sensitive to changes in annual discount rate but highly sensitive to changes in female calf price and BMS number of cows, indicating the importance of considering fluctuations in calf price and potential quality of culled cows' carcasses when estimating the economically optimal parity of culling. The three indicators derived different optimal solutions even in the same mating trial systems, stressing the importance of choice of production indicators when determining the culling strategy and evaluating animal production.

DOI： 10.1017/S0021859611000347

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.2527/jas.2008-0948

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：WILEY  

Heterogeneity of variance among subclasses of an effect is a potential source of bias in genetic evaluation. Degrees of the heterogeneity of variance among farm-market-year-sex (FMYS) subclasses for carcass weight, beef marbling standard number, rib-eye area, rib thickness and subcutaneous fat thickness were investigated in Japanese Black cattle. Consequences of adjusting for the heterogeneity on the predicted breeding values (PBVs) or on the genetic indexes derived from the PBVs of the five carcass traits were assessed. A total of 57 461 records were collected between 1997 and 2002 from steers and heifers fattened at farms across Japan. These records were grouped into 1591 FMYS subclasses. Bartlett's test showed that the degree of the heterogeneity of variance among the FMYS subclasses was sizeable in all traits (P < 0.0001). By applying a two-step adjustment procedure it was possible to reduce the standard deviation, the coefficient of variation and the Gini coefficient of the phenotypic variances by 67.5% to 75.0% in the different traits. The applied adjustment caused a substantial re-ranking of elite dams in the PBV for each trait as well as in the genetic index. This study provided evidence that the applied adjustment reduces the bias in the PBVs due to heterogeneous variances and increases the accuracy of bull-dam selection.

DOI： 10.1111/j.1740-0929.2008.00576.x

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：WILEY  

The objectives of this study were to estimate genetic parameters for gestation length (GL), including estimation of maternal effects, and to investigate the genetic relationships of GL with birth weight and carcass traits in a Japanese Black cattle population. The original data comprised 34 775 records of animals born from October 1999 to August 2003. Two different models were used to analyze the data for GL. The first model (M1) included direct genetic effect of the calf and maternal genetic effect as random effects. The second model (M2) treated GL as a trait of the dam and included direct genetic effects only. M1 was used in bi-variate analysis. The direct and maternal heritabilities for GL estimated from M1 were 0.53 and 0.14, respectively. This result shows that GL is moderately inherited and can be controlled genetically. The direct x maternal genetic correlation for GL was -0.73. Direct genetic correlations of GL with carcass traits were close to zero. However, genetic correlation of maternal GL with carcass weight was moderate (0.25).

DOI： 10.1111/j.1740-0929.2008.00530.x

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：American Society of Animal Science  

Heterogeneity of variance among subclasses of an effect is a potential source of bias in genetic evaluation. The objectives of this study were to quantify the heterogeneity of variance in carcass weight in Japanese Black cattle, to develop an adjustment method to account for the heterogeneity, and to evaluate the effectiveness of the method. A total of 96,950 records were collected from steers and heifers slaughtered from 1997 to 2005. These records were grouped into 2,767 farm-market-year-sex subclasses. Fourteen log-linear models for the variances were set up to estimate the heterogeneous phenotypic variances within subclasses. Schwarz's Bayesian information criterion was used for model selection. The preadjustment of records to a baseline variance was based on maximum likelihood estimates obtained from the selected model. As a result of adjustment, the SD, the CV, and the Gini coefficient for the phenotypic variance decreased by 68.6, 69.8, and 70.1%, respectively. When the top 5% of sires and top 1% of dams were selected, Spearman's rank correlation coefficients between the adjusted and unadjusted data were 0.95 for the selected sires and 0.78 for the selected dams. The effectiveness of the adjustment was evaluated in terms of the ability to predict breeding values, using the results of the successive genetic evaluations. Mean squared error between the parent averages and actual predicted values of the genetic merit for the sires whose progeny had a carcass record only from 2003 to 2005 was significantly reduced by the adjustment (P < 0.05). The results suggest that the genetic evaluation becomes more accurate by adjusting the data using the procedure developed in this study.

DOI： 10.2527/jas.2007-0063

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

The objectives of this study were 1) to investigate the effect of changes in carcass market prices due to bovine spongiform encephalopathy (BSE) occurrences on estimates of genetic parameters and economic weights for carcass traits
and 2) to compare direct and indirect approaches for prediction of genetic merit of Japanese Black cattle for profitability of their progeny. The direct approach utilized estimated breeding values of carcass prices, whereas in the indirect approach, selection indices were constructed as products of economic weights and breeding values of component traits. Data were composed of 80,191 carcass records divided into 5 periods based on changes in carcass prices as a result of occurrences of BSE in Japan and the United States. The periods ranged from a period before occurrence of BSE in Japan to a period of beef import restrictions and a rise in prices. Carcass traits analyzed included HCW, LM area, rib thickness, subcutaneous fat thickness, and marbling score (MS). Price traits included carcass unit price and carcass sale price. Estimates of heritability for price traits were moderate (0.32 to 0.46) and slightly sensitive to changes in carcass market prices. Genetic correlations of HCW and LM area with price traits increased and that between MS and carcass sale price decreased with period, whereas estimates of genetic correlation between MS and carcass unit price were high in all periods (0.96 to 0.98). Economic weights for carcass traits varied with periods because carcass prices were highly sensitive to economic importance of traits. Nevertheless, correlations between within-period breeding values for price traits estimated using direct and indirect approaches were high (0.92 to 0.99). This result indicates that selection realized by direct and indirect approaches will provide very similar results. A comparison among within-approach breeding values estimated in different periods showed that the largest differences in breeding values of sires for price traits were between the periods after occurrences of BSE in Japan and in the United States. Economic effects of BSE occurrences influenced the importance of carcass traits and economic merits of price traits through a change of carcass prices from period to period, irrespective of the approach taken in determining the genetic merit of breeding animals for profitability of their progeny. ©2006 American Society of Animal Science. All rights reserved.

DOI： 10.2527/jas.2005-610

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

The importance of genotype × environment (region or management system) interactions for carcass traits in Japanese Black cattle was investigated using both univariate and multivariate animal models. The univariate approach was used mainly to test the significance of interaction effects. The multivariate approach was used to estimate genetic correlations, which indicated the magnitude of genotype × environment (GE) interactions. The more a genetic correlation deviates from 1, the larger the interaction. From the univariate approach, the addition of genotype × environment (region or management system) interaction (co)variance components resulted in an improved fit of the model for all traits in both cases (P &lt
0.001). However, estimates of genetic correlation between regions obtained from the multivariate approach for hot carcass weight, LM area, rib thickness, s.c. fat thickness, and marbling score were 0.97, 0.95, 0.93, 0.97, and 0.93, respectively. The corresponding estimates between management systems were 0.84, 0.92, 0.84, 0.90, and 0.97, respectively. These results indicate that GE interaction effects on carcass traits of Japanese Black cattle may be biologically unimportant. Therefore, breeding values obtained using the multivariate method would rank sires similarly in all environments. Consequently, carcass traits measured in these two different regions or management systems can be treated as the same traits. ©2005 American Society of Animal Science. All rights reserved.

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：BLACKWELL WISSENSCHAFTS-VERLAG GMBH  

The population structure of the Japanese Brown in Kumamoto Prefecture was investigated with pedigree analysis. Two hundred heifers were randomly sampled, in 1960, 1970, 1980, and 1990. Population genetic parameters, i.e. F-statistics, index of subdivision, generation interval, effective population size, and effective number of sires, were estimated. The effective number of sires decreased, most dramatically, from 1970 to 1980. The average inbreeding coefficient (F-IT) increased, from 0.64% in 1960 to 5.43% in 1990. F-ST increased in parallel with F-IT, while F-IS remained low. From 1960 to 1980, the index of diversity showed a decreasing trend, but this improved a little, with the index at 1.1 in 1990. The generation interval tended to be longer year by year, and was 5.52 during 1980-90. On the other hand, N-c decreased, from 724.6 before 1960 to 40.1 at the present The population structure of the Japanese Brown is not problematical at present, when considering F-IT, but the irreversible inbreeding coefficient (F-ST) increases constantly.

DOI： 10.1111/j.1439-0388.1997.tb00490.x

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記述言語：日本語   出版者・発行元：日本動物遺伝育種学会  

口之島牛は鹿児島県トカラ列島の口之島において、明治から大正期にかけて放牧されていた日本在来牛が野生化した日本で唯一の野生化牛の集団である。これまでに、我が国の主要な肉用牛である黒毛和種や日本在来牛といわれる見島牛等においては経済形質や遺伝性疾患に関する種々の遺伝子の遺伝子頻度と分布は明らかにされているが、口之島牛におけるそれらに関する報告は少ない。そこで、本研究では口之島牛の集団における経済形質、遺伝性疾患および毛色に関与する遺伝子の対立遺伝子頻度と分布を調べ、それらを黒毛和種および見島牛の集団と比較することで、口之島牛の集団の遺伝的特徴について検討した。32 頭の口之島牛より採取されたDNAサンプルを用い、脂肪酸組成や枝肉形質に関与することが報告されている&lt;I&gt;NCAPG&lt;/I&gt;、&lt;I&gt;FASN&lt;/I&gt;、&lt;I&gt;SCD&lt;/I&gt; および&lt;I&gt;SREBP-1&lt;/I&gt; 遺伝子、遺伝性疾患の第XI 因子欠乏症の原因遺伝子である&lt;I&gt;F11&lt;/I&gt; 、毛色に関与する&lt;I&gt;MC1R&lt;/I&gt; 遺伝子についてPCR 法あるいはPCR-RFLP法により遺伝子型判定を行い、黒毛和種および見島牛の集団の結果と比較した。その結果、&lt;I&gt;NCAPG&lt;/I&gt; 遺伝子については、黒毛和種では&lt;I&gt;G&lt;/I&gt; および&lt;I&gt;T&lt;/I&gt; の両対立遺伝子が検出されたのに対し、口之島牛と見島牛では&lt;I&gt;T&lt;/I&gt; に固定され、&lt;I&gt;FASN&lt;/I&gt; 遺伝子については、黒毛和種では&lt;I&gt;TW&lt;/I&gt; および&lt;I&gt;AR&lt;/I&gt; の両対立遺伝子が検出されたのに対し、口之島牛では&lt;I&gt;AR&lt;/I&gt; に、見島牛では&lt;I&gt;TW&lt;/I&gt; に固定されていた。&lt;I&gt;SCD&lt;/I&gt; 遺伝子については、黒毛和種、口之島牛、見島牛のいずれでも&lt;I&gt;A&lt;/I&gt; と&lt;I&gt;V&lt;/I&gt; の両対立遺伝子が検出され、&lt;I&gt;SREBP-1&lt;/I&gt; 遺伝子については、黒毛和種および見島牛では&lt;I&gt;S&lt;/I&gt; および&lt;I&gt;L&lt;/I&gt; の両対立遺伝子が検出されたのに対し、口之島牛では&lt;I&gt;L&lt;/I&gt; に固定されていた。&lt;I&gt;F11&lt;/I&gt; 遺伝子については、黒毛和種では(+) および(-) の両対立遺伝子が検出されたのに対し、口之島牛、見島牛では(+) に固定され、&lt;I&gt;MC1R&lt;/I&gt; 遺伝子については、黒毛和種では&lt;I&gt;E&lt;/I&gt;&lt;SUP&gt;D&lt;/SUP&gt; および&lt;I&gt;E&lt;/I&gt;&lt;SUP&gt;+&lt;/SUP&gt; 対立遺伝子が検出され、口之島牛では&lt;I&gt;E&lt;/I&gt;&lt;SUP&gt;+&lt;/SUP&gt; および&lt;I&gt;e&lt;/I&gt; 対立遺伝子が検出され、見島牛では&lt;I&gt;E&lt;/I&gt;&lt;SUP&gt;+&lt;/SUP&gt; 対立遺伝子に固定されていた。これらの結果より、口之島牛は他のウシの集団と地理的に隔離された環境で、小さな集団として維持されてきたこと等の理由により、黒毛和種や見島牛とは異なる遺伝的特徴を持つ集団を形成していると考えられた。

DOI： 10.5924/abgri.42.11

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記述言語：英語   掲載種別：研究発表ペーパー・要旨（国際会議）   出版者・発行元：SOC STUDY REPRODUCTION  

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記述言語：日本語   出版者・発行元：岡山大学農学部  

Japanese Black cattle are the predominant beef breed in Japan. This breed has excellent meat quality, especially degree of (intramuscular) marbling. Degree of marbling was measured at the 6th to 7th rib section and according to the Beef Marbling Standard with scores 1 to 12 (so-called BMS), with number 12 being the best. BMS is used with business deal of beef carcass and has strongly effect on selling price of carcass. On the other hands, more degree of marbling on top round (MTR) is better carcass unit price in same BMS, because of good price of part of thigh. MTR has been focused in recent years. However, MTR is unclear how to evaluate, therefore, collection of records and genetic evaluations are not enough. In this study, records of MTR were collected and then, genetic parameters for BMS and MTR of Japanese Black were estimated. The original data were 11,052 carcass records collected from April in 2008 to June in 2009 at the Agura Farm. Only information from abattoirs having more than 20 records and feedlot farms having more than 10 records were used. This resulted in a total of 10,990 records. In this study, pedigree information was traced back to two generations. An animal model that included all relationships among all animals was used as a statistical model. The fixed effects included sex, farm, abattoir and the combination of slaughter year and month. Slaughter age was fitted as linear covariables. Genetic parameters were estimated using REMLF90 and THRGIBBS1F90 programs. The estimates of heritability were moderately high (0.37 to 0.44) for MTR treated as threshold traits. The estimates of phenotypic and genetic correlations between BMS and MTR were very high (0.87 and 0.98, respectively). These indicate that MTR can be improved genetically and improvement of MTR can treat BMS as indicator.

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記述言語：日本語   出版者・発行元：岡山大學農學部  

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記述言語：日本語   出版者・発行元：日本動物遺伝育種学会  

DOI： 10.5924/abgri2000.36.29

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DOI： 10.5924/abgri2000.36.29

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記述言語：日本語   出版者・発行元：地域農林経済学会  

DOI： 10.7310/arfe1965.43.51

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記述言語：日本語   出版者・発行元：日本動物遺伝育種学会  

DOI： 10.5924/abgri2000.35.25

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DOI： 10.5924/abgri2000.35.25

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記述言語：日本語   出版者・発行元：地域農林経済学会  

DOI： 10.7310/arfe1965.43.51

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記述言語：日本語   出版者・発行元：公益社団法人 日本畜産学会  

本研究の目的は，アンケート調査を行い，肉牛飼養者の属性や意識の差異が農家ごとの枝肉価格と枝肉形質の最良線形不偏推定値（BLUE）に与える影響を調べることであった．アンケート調査は，安愚楽牧場と契約している農家を対象に行い，分析には肥育農家91戸のデータを用いた．最良線形不偏推定値（BLUE）の推定には，安愚楽牧場で2004年1月から2005年3月までに出荷された20,346頭の枝肉成績を用いた．農家ごとの枝肉価格と枝肉形質に関するBLUE値を目的変数とし，農家の属性や意識を取り入れ最小2乗分散分析を行った．分析の結果，経済性と生きがいをともに重視している農家の方が良質の枝肉を生産していることが明らかとなった．さらに，枝肉単価と飼養規模の間には2次曲線の関係があり，規模が大きくなるにつれ，枝肉単価は逓減し，932頭を境に増加していくことが明らかとなった．

DOI： 10.2508/chikusan.77.289

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記述言語：日本語   出版者・発行元：公益社団法人 日本畜産学会  

全国的な種牛評価の可能性を遺伝的結合度および遺伝率推定値の点から検討し，その結果をふまえて全国的な種牛評価のための最適な数学モデルに関して検討した．1997&amp;sim;2002年までに全国に分布する(有)安愚楽共済牧場傘下の肥育農家から出荷された黒毛和種肥育牛のフィールド記録を用いた．数学モデルとして，母数効果の取り上げ方が異なる6つのモデルを設定し，産肉性形質に関する遺伝率を推定し，育種価を予測した．肥育農家を単位とする分集団間の遺伝的結合度が確認できたことおよび遺伝率の推定値が中程度であったことから，全国規模での種牛評価が可能であると推察される．また，予測育種価の予測誤差分散（PEV），赤池の情報量規準（AIC）および自由度調整済寄与率を指標としてモデルの選択を行った結果，全ての母数効果を組み合わせ効果として取り上げたモデルもしくは性の効果のみを組み合わせ効果から外したモデルが最適なモデルであると推察される．種牛評価を全国規模に拡大することで，より効率的な育種改良を行うことができると考えられる．

DOI： 10.2508/chikusan.75.353

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記述言語：日本語   出版者・発行元：日本中央競馬会競走馬総合研究所  

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DOI： 10.1294/jes.14.81

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記述言語：英語   出版者・発行元：日本ウマ科学会  

DOI： 10.1294/jes.14.81

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記述言語：日本語   出版者・発行元：公益社団法人 日本畜産学会  

岩手県南地方における黒毛和種集団の育種の妥当性を検証するため岩手県前沢町から出荷された黒毛和種肥育牛3,467頭のフィールド記録を用いて，産肉性形質に関する遺伝的パラメータ，育種価および遺伝的趨勢を推定した．産肉性形質に与える有意な環境要因の影響では，BMSの最良線形不偏推定量が年を経るごとに減少することが注目された．産肉性形質の遺伝率はBMS 0.66, DG 0.51，枝肉重量0.64，ロース芯面積0.36，バラ厚0.25，皮下脂肪厚0.33といずれも中程度から高めであった．BMSとその他の産肉性形質の間の遺伝相関はDG 0.1，枝肉重量0.18，ロース芯面積0.48，バラ厚0.37，皮下脂肪厚－0.24であった．遺伝的趨勢を見ると1991年を境としてBMSと皮下脂肪厚を重視した改良が進められ，枝肉重量は考慮されていない様子がうかがえた．一方，同年を境に同町産の肥育牛の肉質等級は年々低下する傾向にあるが，この原因は改良以外の要因にあると推察された．

DOI： 10.2508/chikusan.74.187

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記述言語：日本語   出版者・発行元：日本動物遺伝育種学会  

ディファレンシャルディスプレイ (DD) 法が遺伝子発現量を多サンプル間で比較するために使われるには、得られたPCR産物の鎖長 (BP) のデータに再現性があること、並びに発現量が定量的に捉えられることが必要である。<BR>まず、PCR産物のBPと遺伝子発現量に相当するその産物の生成量 (IOD) についての電気泳動像の画像解析による最適な数値化の方法を検討した。BPについては、PCR産物の移動度とゲル両端と中央の3つのレーンで泳動した分子量マーカーの移動度の情報を用いて計算するBP (A) が最適な数値化の方法であり、IODについては、PCR産物のバンドにおけるシグナル強度の測定値をそのまま用いるIOD (A) およびその測定値を同一レーン上にある全てのバンドのシグナル強度の和で割るIOD (P) がそれぞれ準最適および最適とされた。次に、BP (A) 、IOD (A) およびIOD (P) について、ゲル間、泳動レーン間およびRT-PCR反応間の変動を検討した結果、BP (A) についてはゲル間と泳動レーン間において有意な変動が検出されたが、RT-PCR反応間では有意な変動は検出されなかった。一方、IOD (A) とIOD (P) については泳動レーン間では有意な変動は検出されなかったが、ゲル間とRT-PCR反応間で有意な変動が検出された。これら分散分析の結果から各要因の分散成分を推定した。最後に、それらの結果を受けて、4通りの反復パターンで得られたBPおよびIODの測定値の変動係数から、大規模遺伝子発現プロファイリング作成に最適な反復回数について考察した。

DOI： 10.5924/abgri2000.30.11

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記述言語：日本語   出版者・発行元：公益社団法人 日本畜産学会  

黒毛和種の常染色体性劣性遺伝性疾患である&lt;i&gt;Claudin-16&lt;/i&gt; (&lt;i&gt;CL-16&lt;/i&gt; ) 欠損症の原因となる変異遺伝子 (原因遺伝子&lt;i&gt;d&lt;/i&gt; ) と産肉成績との関連性についてアソシエーション解析を行った. 原因遺伝子&lt;i&gt;d&lt;/i&gt; キャリア種雄牛3頭 (Sire-1～-3) の産子である肥育牛464頭とSire-1の産子である繁殖雌牛140頭の&lt;i&gt;CL-16&lt;/i&gt; 遺伝子型を検査した結果, 肥育牛では正常遺伝子ホモ型 (&lt;i&gt;DD&lt;/i&gt; ) 234頭およびキャリア (&lt;i&gt;Dd&lt;/i&gt; ) 230頭であった. 繁殖雌牛では正常遺伝子ホモ型 (&lt;i&gt;DD&lt;/i&gt; ) 60頭およびキャリア (&lt;i&gt;Dd&lt;/i&gt; ) 80頭であった. 3頭のキャリア種雄牛は共通した祖先を持ち, その共通祖先牛はキャリア牛であることが確認されている. &lt;i&gt;CL-16&lt;/i&gt; 遺伝子型と産肉成績との関連性を調べるため, &lt;i&gt;CL-16&lt;/i&gt; 遺伝子型を要因として, 産肉成績について最小二乗分散分析を行った. 種雄牛間の変動は皮下脂肪厚を除いてすべての形質で有意であった. 性の影響は枝肉重量で, 農家についてはBMSナンバー, 枝肉重量及びバラの厚さで有意差が認められた. このように産肉成績に関与する環境要因を取り除いても&lt;i&gt;CL-16&lt;/i&gt; 遺伝子型の産肉成績には有意差は見られなかった. 繁殖雌牛のSire-1産子140頭の産肉形質に関する予測育種価も, 原因遺伝子&lt;i&gt;d&lt;/i&gt; と有意に関連する結果は得られなかった (P&gt;0.05). また, 136頭で構成されるSire-1の父方半兄弟家系を用いて連鎖解析を行ったが, &lt;i&gt;CL-16&lt;/i&gt; 遺伝子座領域 (約30cM) は上記の形質に関する有意な連鎖は認められなかった (P&gt;0.05). したがって, &lt;i&gt;CL-16&lt;/i&gt; 欠損症の発症を避けるため原因遺伝子&lt;i&gt;d&lt;/i&gt; を集団から排除しても産肉成績に影響する危険性は少ないと考えられる.

DOI： 10.2508/chikusan.73.19

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記述言語：日本語   出版者・発行元：動物遺伝育種研究  

ディファレンシャルディスプレイ (DD) 法が遺伝子発現量を多サンプル間で比較するために使われるには、得られたPCR産物の鎖長 (BP) のデータに再現性があること、並びに発現量が定量的に捉えられることが必要である。&lt;BR&gt;まず、PCR産物のBPと遺伝子発現量に相当するその産物の生成量 (IOD) についての電気泳動像の画像解析による最適な数値化の方法を検討した。BPについては、PCR産物の移動度とゲル両端と中央の3つのレーンで泳動した分子量マーカーの移動度の情報を用いて計算するBP (A) が最適な数値化の方法であり、IODについては、PCR産物のバンドにおけるシグナル強度の測定値をそのまま用いるIOD (A) およびその測定値を同一レーン上にある全てのバンドのシグナル強度の和で割るIOD (P) がそれぞれ準最適および最適とされた。次に、BP (A) 、IOD (A) およびIOD (P) について、ゲル間、泳動レーン間およびRT-PCR反応間の変動を検討した結果、BP (A) についてはゲル間と泳動レーン間において有意な変動が検出されたが、RT-PCR反応間では有意な変動は検出されなかった。一方、IOD (A) とIOD (P) については泳動レーン間では有意な変動は検出されなかったが、ゲル間とRT-PCR反応間で有意な変動が検出された。これら分散分析の結果から各要因の分散成分を推定した。最後に、それらの結果を受けて、4通りの反復パターンで得られたBPおよびIODの測定値の変動係数から、大規模遺伝子発現プロファイリング作成に最適な反復回数について考察した。

DOI： 10.5924/abgri2000.30.11

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記述言語：日本語  

CiNii Article

CiNii Books

J-GLOBAL

researchmap

記述言語：日本語  

J-GLOBAL

researchmap

記述言語：日本語  

J-GLOBAL

researchmap

記述言語：日本語  

J-GLOBAL

researchmap

記述言語：日本語  

J-GLOBAL

researchmap