I.C. Cheong

Growth hormone-releasing hormone (GHRH) polymorphisms associated with carcass traits of meat in Korean cattle

BackgroundCold carcass weight (CW) and longissimus muscle area (EMA) are the major quantitative traits in beef cattle. In this study, we found several polymorphisms of growth hormone-releasing hormone (GHRH) gene and examined the association of polymorphisms with carcass traits (CW and EMA) in Korean native cattle (Hanwoo).ResultsBy direct DNA sequencing in 24 unrelated Korean cattle, we identified 12 single nucleotide polymorphisms within the 9 kb full gene region, including the 1.5 kb promoter region. Among them, six polymorphic sites were selected for genotyping in our beef cattle (n = 428) and five marker haplotypes (frequency > 0.1) were identified. Statistical analysis revealed that -4241A>T showed significant associations with CW and EMA.ConclusionOur findings suggest that polymorphisms in GHRH might be one of the important genetic factors that influence carcass yield in beef cattle. Sequence variation/haplotype information identified in this study would provide valuable information for the production of a commercial line of beef cattle.

Titin-cap (TCAP) polymorphisms associated with marbling score of beef

Marbling score (MS) is the major qualitative trait that affects carcass quality in beef cattle. In this study, we examined the association between genetic polymorphisms of the titin-cap gene (TCAP) and carcass traits in Korean native cattle (also known as Hanwoo). By direct DNA sequencing in 24 unrelated Korean cattle, we identified five sequence variants in 1.2kb of TCAP. Among them, four common polymorphic sites were selected for genotyping in the beef cattle (n=437). Pair-wise linkage analysis with four polymorphisms showed strong linkage disequilibrium (LD), and three major haplotypes (freq.>0.1) were constructed. Statistical analysis revealed that polymorphisms in intron1 (g.346G>A) and exon2 (g.592-597CTGCAG[Leu-Gln]insdel) showed significant association with marbling score (P(cor.)=0.003 and 0.02, respectively). One haplotype, ht2[C-G-G-del], also showed significant association with MS (P(cor.)=0.0004). Our findings suggest that polymorphisms in TCAP might be among the important genetic factors involved in carcass quality in beef cattle.

Detection of Novel Mutations in the FABP3 Promoter Region and Association Analysis with Intramuscular Fat Content in Pigs

Intramuscular fat content(lMF) is considered as one of major economic traits in the pig breeding and industry. In general, high IMF results in better meat quality. Several approaches to detect quantitative trait 10ci( QTL) for IMF indicated a strong possibility of the existence of a QTL related to IMF between the microsatellite marker SW71 and SW1881 on SSC6q. Porcine FABP3 has been considered as a candidate gene affecting IMF due to its physiological roles and position on the pig genome. Two novel mutations, g.-114T> C and g.-158T>G were detected by duplicate sequencing of the porcine FABP3 promoter region. These two mutations were identified as absolute linkage disequilibrium. The g.-158T> G mutation was used for investigating relationships with growth and fat deposition traits. The GG genotype of the g.-158T> G polymorphism showed highly negative effects(P

A Study on Estimation of Individual Growth Curve Parameters and their Relationships with Meat Quality Traits of Crossbred between Korean Native Boars and Landrace Sows

This study was conducted to estimate the growth curve parameters of crossbreds between Korean native boars and Landrace sows and their relationships with meat qualities. The data used were weight-age data and carcass data from 131 males and 122 females raised at N.L.R.I in Korea. Growth curve parameters were estimated from nonlinear regression using Gompertz model individually. Average mature weight(A), average maturing rate(k), and average inflection point( tI ) showing maximum growth rate estimated were 179.54 ± 6.06kg, 0.3154 ± 0.0059, and 5.50 ± 0.11 months in females, and 179.84 ± 6.33kg, 0.3049 ± 0.0061, and 5.24 ± 0.13 months in males, respectively. For the growth curve parameters and derived statistics, the phenotypic correlations of maturing rate with gain rate at inflection, mature weight, and inflection point were .30, .77, and .93 in male, and .31, .78 and .94 in female, respectively. Matrure weight was positively correlated to the inflection point as + .89 in both male and female, indicating that late maturing pigs with lower k had longer maturing period with increasing gain rate and reached point of inflection later than early maturing pigs with higher k, and grew to larger mature weight. Backfat thickness and crude fat contents were correlated with mature weight positively in male and negatively in female, and correlated with gain rate at inflection point positively in both male and female, of which coefficients were as high as .42 and .50 in male, respectively.

Establishment of genetic characteristics and individual identification system using microsatellite loci in domestic beef cattle.

DNA marker information is used to identify or distinguish cattle breeds or individual animal. The purpose of this study was to apply Bovine Genotypes Kit Version 1.1/2.1 to bovine DNA samples (National Institute of Animal Science) taken from Australian / American beef (n=148), Holstein beef (n=170) and Hanwoo cattle (n=177) bred in Jeongeub, Jeonbuk, Korea, so that it could distinguish Hanwoo breed. The Bovine Genotype Kits consist of 16 ISAG MS markers, which were used to build a database of genotypes in each group. Genotyping results were analyzed using MS Tool kit and Phylip program to create phylogenetic tree. The GeneClass 2.0 was used to estimate breed identification. These analyses found that this kit had 100% capacity to distinguish Hanwoo beef, 95.3% capacity to differentiate Australian / American beef and 90% capacity to identify Korean Holstein steer beef. Hence, it is expected that 16 commercial microsatellite markers is useful to categorizegenetic characteristics of Hanwoo breed and also identify Hanwoo individuals and the origin of beef. In particular, it is expected that these markers will be advantageous in discriminating domestic Holstein beef from Australian / Americanbeef. (Key words : Hanwoo, Microsatellite, Individual identification, Geneclass analysis, Phylogenetic analysis)

A study of Association of the H-FABP RFLP with Economic Traits of Pigs

The purpose of this study was to detect association between genetic variation and economic trait in the porcine heart type fatty acid-binding protein gene as a candidate gene for the traits related with growth and meat quality in pigs. The H-FABP is a 15-kDa protein expressed in several tissues with high demand for fat metabolism such as cardiac and skeletal muscle and lactating mammary gland. H-FABP is small intracellular protein involved in fatty acid transport from the plasma membrane to the site of -oxidation and/or triacylglycerol or phospholipid synthesis. In this study, H-FABP PCR-RFLP was performed in F population composed of 214 individuals from an intercross between Korean Native Boars and Landrace sows. PCR products from two primer sets within H-FABP gene were amplified in 850bp and 700bp. Digestion of PCR products with the restriction digestion enzymes HaeⅢ and HinfⅠ, revealed fragment length polymorphisms(RFLPs). The genotype frequencies from H-FABP/HaeⅢ was .29 for genotype DD, .53 for genotype Dd, and .15 for genotype dd, respectively. The genotype frequencies of HH, Hh, and hh from H-FABP/HinfⅠ was .38, .41 and .20, respectively, in the population. Relationships between their genotypes and economic traits were estimated. In H-FABP/HaeⅢ locus, there were specific genotypes(Dd and dd) associated with economic traits such as body weights at 3, 5, 12, and 30 week of age (p〈.05 to .001). The ‘d’ allele was associated with gaining of body weight. In H-FABP/HinfⅠ locus, Genotypes of HH and Hh associated with growth traits such as body weights at 5, 12, and 30 week of age (p〈.05 or p〈.001) and back fat thickness, body fat including abdominal and trimmed fat (p〈.001) and intramuscular fat(p〈.05) The ‘H’ allele was positively associated with gaining of body weight and fatness deposition. In conclusion, a significant association of the H-FABP gene from its genetic variation was found on body weight, intramuscular fat and backfat thickness.

Association Study between Porcine LEPR-derived Microsatellite Polymorphisms and Economic Traits

ABSTRACT The leptin receptor gene( LEPR ) produces a high affinity receptor that mediates the regulation of the leptingene. Leptin secreted from adipose tissue plays an important role in regulating feed intake and energy balance.In this study, a microsatellite marker within LEPR was selected and genotyped for the F 2 population composedof 354 individuals from an intercross between Korean Native boars and Landrace sows. Totally, six alleles(255, 259, 261, 263, 265 and 267bp) and nineteen genotypes were detected in the population, of which theCE (261/265), CC (261/261) and EE (265/265) types were observed by 20.0%, 10.1% and 9.6%, respectively.Relationships between their genotypes and economic traits were analyzed. We found specific genotypesassociated with economic traits such as body weight at 12 weeks of age/body fat including abdominal andtrimmed fat/shear force (P 0.001), body weight of 30 weeks of age (P 0.01) and body weight of 3 weeksof age/back fat thickness (P 0.05). The DD (263/263) and DF (263/267) types were associated with bodyweight at 3, 5, 12 and 30 weeks of age. The DF (263/267) type showed a highly significant effect on backfat thickness and body fat including abdominal and trimmed fat. The DF (263/267) type showed positive effecton shear force, whereas the BB (259/259) and DD (263/263) types negatively affected on tenderness.(

Identification of Quantitative Trait Loci(QTL) for Meat Color Trait on Chromosome 7 in Pig

ABSTRACT The objective of this study was to identify the quantitative traits loci(QTL) for meat quality traits in pigs.Three-generation resource population was constructed from a cross between Korean native boars and Landracesows. The resource population including founders, F 1 and F 2 was genotyped for 23 microsatellite markers onchromosome 7. The sex average total length of linkage map on chromosome 7 was estimated 154.6 cM. Meatquality traits including meat pH, meat color, drip loss, shear force, heating loss, crude fat, crude protein, crudeash and water content in muscle were collected from F 2 animals. For the QTL mapping, we used F 2 QTLAnalysis Servlet of QTL express for web-based QTL mapping tools(http://qtl.cap.ed.ac.uk/) . The QTLs forCIE-a and CIE-b on SSC7 were significantly detected at 1% and 5% chromosome-wide level, respectively.( Key words : QTL mapping, Meat color, Linkage mapping, Microsatellite, Korean native boar)Corresponding author : T. H. Kim, National Livestock Research Institute, R.D.A, Omockchun-dong Suwon 441-706,Korea. Tel: 031-290-1603, E-mail : kth6160@rda.go.kr

A Missense Mutation in Exon 5 of the Bovine Growth Hormone Gene

Growth Hormone (GH) gene is a member of gene family through the evolutionary process from a small common ancestral gene by a series of gene duplications. The role of the GH in growth and performance controls has been extensively studied in human, mice and livestock. Many researchers have considered GH as a strong candidate gene for evaluation of genetic polymorphisms that could be associated with economic traits in cattle. We report here a novel missense mutation within the exon 5 of the bovine Growth Hormone (bGH) gene. We could amplified 522 bp fragments from eight unrelated Hanwoo cattle by PCR, then, subsequently cloned and sequenced. An Msp I RFLP corresponding to a C to T transition was observed at position 2258 nt. From this result, we could predict a missense mutation (Arg to Trp) at codon 166 in a highly conserved region among many mammals. Codominant Mendelian segregation of the two alleles, Msp I (+) and Msp I (Ĕ), was observed in two full-sib F2 families (n = 32, African taurine Bos taurus × African zebu Bos indicus) and eight half-sib Hanwoo families. For the availability of genetic marker, we have performed PCR-RFLP with a large number of individual animals from 15 different cattle breeds (European and Asian taurines, and African indicines). Consideration of breed frequencies of Msp I (Ĕ) allele in relation to breed type and their geographic origins, shows higher frequencies in humped breeds or Asian cattle breeds than in humpless or European breeds. This result indicates that the missense mutation can be contributed the functional significance such as the signal transduction through the receptor binding, also may be used as a marker for selection of the economic traits in Hanwoo.

Linkage Map and Quantitative Trait Loci(QTL) on Pig Chromosome 6

ABSTRACT The objective of this study was to identify the quantitative traits loci(QTL) for economically important traitssuch as growth, carcass and meat quality on pig chromosome 6. A three generation resource population wasconstructed from cross between Korean native boars and Landrace sows. A total of 240 F 2 animals wereproduced using intercross between 10 boars and 31 sows of F 1 animals. Phenotypic data including body weightat 3 weeks, backfat thickness, muscle pH, shear force and crude protein level were collected from F animals.Animals including grandparents(F 0 ), parents(F 1 ) and offspring(F 2 ) were genotyped for 29 microsatellitemarkers and PCR-RFLP marker on chromosome 6. The linkage analysis was performed using CRI-MAPsoftware version 2.4(Green et al ., 1990) with FIXED option to obtain the map distances. The total length ofSSC6 linkage map estimated in this study was 169.3cM. The average distance between adjacent markers was6.05cM. For mapping of QTL, we used F 2 QTL Analysis Servlet of QTL express, a web-based QTL mappingtool(http://qtl.cap.ed.ac.uk).Five QTLs were detected at 5% chromosome-wide level for body weight of 3 weeks of age, shear force,meat pH at 24 hours after slaughtering, backfat thickness and crude protein level on SSC6.(