Shil Jin

Investigation of MC1R SNPs and Their Relationships with Plumage Colors in Korean Native Chicken

The melanocortin 1 receptor (MC1R) gene is related to the plumage color variations in chicken. Initially, the MC1R gene from 30 individuals was sequenced and nine polymorphisms were obtained. Of these, three and six single nucleotide polymorphisms (SNPs) were confirmed as synonymous and nonsynonymous mutations, respectively. Among these, three selected SNPs were genotyped using the restriction fragment length polymorphism (RFLP) method in 150 individuals from five chicken breeds, which identified the plumage color responding alleles. The neighbor-joining phylogenetic tree using MC1R gene sequences indicated three well-differentiated different plumage pigmentations (eumelanin, pheomelanin and albino). Also, the genotype analyses indicated that the TT, AA and GG genotypes corresponded to the eumelanin, pheomelanin and albino plumage pigmentations at nucleotide positions 69, 376 and 427, respectively. In contrast, high allele frequencies with T, A and G alleles corresponded to black, red/yellow and white plumage color in 69, 376 and 427 nucleotide positions, respectively. Also, amino acids changes at position Asn23Asn, Val126Ile and Thr143Ala were observed in melanin synthesis with identified possible alleles, respectively. In addition, high haplotype frequencies in TGA, CGG and CAA haplotypes were well discriminated based on the plumage pigmentation in chicken breeds. The results obtained in this study can be used for designing proper breeding and conservation strategies for the Korean native chicken breeds, as well as for the developing breed identification markers in chicken.

Construction of Genetic Linkage Map using Microsatellite and SNP Markers in Korean Native Chicken

Chicken is one of the major livestock, especially for supplying proteins to human. The chicken genome size is approximately one-third compared with that of the human genome and regarded as a valuable model animal for genetics and development biology. In this study, we constructed the genetic linkage map for Korean native chicken (KNC) using 131 microsatellite (MS) and 8 single nucleotide polymorphism (SNP) markers. As a result, the total map length was calculated as 2729.4 cM and the average genetic distance between markers was 19.64 cM. The marker orders and genetic distances were well matched with the consensus linkage map except for the physical order of ADL0278 and MCW0351 in GGA8. In addition, the recombination rates in marcrochromosomes were 3.7 times higher than that of microchromosomes. The average numbers of alleles, expected heterozygosity (Hexp) and polymorphic information content (PIC) values were calculated as 5.5, 0.63 and 0.58, respectively. These results will give useful information for the understanding of genetic structure and QTL studies in KNC.

Association of SNPs in ODC and PRDM16 with Body Weight Traits in Korean Native Chicken

Both ODC and PRDM16 genes were known to be associated with body weight traits in chicken. These two genes were located on GGA3 and GGA21, respectively, where the QTLs of body weights are located. Therefore, the objectives of this study were to identify the SNPs in these two genes and their associations with body weight traits in Korean native chicken. Fluidigm Dynamic Array integrated fluidic circuits (IFCs) assay was used to genotype 7 SNPs consisting g.-353C>T, g.2136A>G, g.2524T>C, g.3607C>T SNPs of the ODC gene, and g.182216C>T, g.182290A>T, g.182491A>T SNPs of the PRDM16 gene. Statistical analysis showed that g.2136A>G SNP of the ODC was associated with body weight at 20 weeks of age and slaughter weight, and g.3607C>T SNP of the ODC was associated with body weight at 2 weeks of age. Association between g.182216C>T SNP of the PRDM16 and body weight at 12 weeks of age has also been revealed. In addition, g.182491A>T SNP of PRDM16 has significant correlation with body weight (BW) at 8 weeks, BW at 10 weeks and BW at 14 weeks of age. These results suggested that both ODC and PRDM16 could be strong candidate genes for body weight traits in Korean native chicken.

Genetic Parameters for Growth-Related Traits in Korean Native Chicken

Body and carcass weights are always being main focus in poultry industry. The aim of current study was to estimate the heritability, genetic and phenotypic correlations of growth-related traits in Korean native chicken. A total of 596 chickens representing five lines of Korean native chicken (Black, Gray-Brown, Red-Brown, White, and Yellow-Brown) were reared under the standard breeding procedures in the National Institute of Animal Science (NIAS), Korea. Their body weights were observed every two weeks from hatched to 20 weeks of age. In addition, shank length and carcass weight were also measured before and after slaughter, respectively. The ASReml-R program was used to compute genetic parameters. The body weight traits were moderate to high heritability values (ranged 0.29∼0.63). The heritablilites of carcass weight (h 2 =0.20) and shank length (h 2 =0.20) were categorized as moderate. Moreover, both genetic and phenotypic correlations were ranged form 0.62 to 0.99 and ranged from 0.42 to 0.98, respectively. These findings can be useful information for quantitative genetic studies and breeding plan of Korean native chicken.

Effect of combination of chitosan coating and gamma irradiation on the foodborne pathogen reduction and nutritional properties of chicken egg.

The effect of combination of chitosan coating and gamma irradiation on Escherichia coli inactivation and nutritional properties of shell egg was investigated. The E. coli inoculated on shell egg was not detected by 2 kGy of gamma irradiation at day 0 and/or chitosan coating (1%, pH 5.0) after 3 days of storage. There was no E. coli detected thereafter. In the contents of moisture, crude fat, crude protein, ash, retinol, phospholipid, and minerals, no difference was found by treatment combination. However, the contents of cholesterol and carotenoids were reduced by irradiation of 2 kGy (P<0.05). Results suggest that the combination of gamma irradiation (2 kGy) and chitosan coating (1%) can be a good method to improve the safety and prolonged

The Possibility of TBC1D21 as a Candidate Gene for Teat Numbers in Pigs.

Based on a quantitative traits locus (QTL) study using a F2 intercross between Landrace and Korean native pigs, a significant QTL affecting teat numbers in SSC7 was identified. The strong positional candidate gene, TBC1D21, was selected due to its biological function for epithelial mesenchymal cell development. Sequence analysis revealed six single nucleotide polymorphisms (SNPs) in the TBC1D21 gene. Among these, two SNP markers, one silent mutation (SNP01) for g.13,050A>G and one missense mutation (SNP04) for c.829A>T (S277C), were genotyped and they showed significant associations with teat number traits (p value = 6.38E-05 for SNP01 and p value = 1.06E-07 for SNP04 with total teat numbers). Further functional validation of these SNPs could give valuable information for understanding the teat number variation in pigs.

Estimation of heritability and genetic correlation of body weight gain and growth curve parameters in Korean native chicken

Objective This study estimated the genetic parameters for body weight gain and growth curve parameter traits in Korean native chicken (KNC). Methods A total of 585 F1 chickens were used along with 88 of their F0 birds. Body weights were measured every 2 weeks from hatching to 20 weeks of age to measure weight gain at 2-week intervals. For each individual, a logistic growth curve model was fitted to the longitudinal growth dataset to obtain three growth curve parameters (α, asymptotic final body weight; β, inflection point; and γ, constant scale that was proportional to the overall growth rate). Genetic parameters were estimated based on the linear-mixed model using a restricted maximum likelihood method. Results Heritability estimates of body weight gain traits were low to high (0.057 to 0.458). Heritability estimates for α, β, and γ were 0.211±0.08, 0.249±0.09, and 0.095±0.06, respectively. Both genetic and phenotypic correlations between weight gain traits ranged from −0.527 to 0.993. Genetic and phenotypic correlation between the growth curve parameters and weight gain traits ranged from −0.968 to 0.987. Conclusion Based on the results of this study population, we suggest that the KNC could be used for selective breeding between 6 and 8 weeks of age to enhance the overall genetic improvement of growth traits. After validation of these results in independent studies, these findings will be useful for further optimization of breeding programs for KNC.

Investigation of Microsatellite Markers for Traceability and Individual Discrimination of Korean Native Ducks

Recently, duck meat consumption has been rapidly increased because consumers recognized duck meat for healthy food. In relation to this, Korean duck industry need to develop Korean native duck (KND) breed for both conservation perspective and self-sufficient of the breeding stocks. In this study, 24 microsatellite (MS) markers were investigated for classification of KND and commercial duck (CD) breeds in the Korean market. Using these MS markers, the calculated number of alleles (K), expected heterozygosity (He) values and polymorphic information contents (PIC) were 1 16, 0 0.865 and 0 0.841, respectively. Also, the expected probability of identical values in random individuals (PI), random sib (PIsib) and random half-sib (PIhalf-sib) were estimated as 1.64×10 -16 , 2.60×10 -7 and 1.30×10 -12 , respectively. The results indicated that the expected probabilities of identity powers were enough for the individual identification. However, KND and CD breeds were not fully discriminated well using the 24 MS markers, which may CD and KND has shared same origin or crossbred. Therefore, further studies will be ultimately needed for developing a genetically pure line of KND breed even though the DNA markers used. Finally, these results will provide useful information for individual traceability system in ducks.

Variance Component Quantitative Trait Locus Analysis for Body Weight Traits in Purebred Korean Native Chicken

Quantitative trait locus (QTL) is a particular region of the genome containing one or more genes associated with economically important quantitative traits. This study was conducted to identify QTL regions for body weight and growth traits in purebred Korean native chicken (KNC). F1 samples (n = 595) were genotyped using 127 microsatellite markers and 8 single nucleotide polymorphisms that covered 2,616.1 centi Morgan (cM) of map length for 26 autosomal linkage groups. Body weight traits were measured every 2 weeks from hatch to 20 weeks of age. Weight of half carcass was also collected together with growth rate. A multipoint variance component linkage approach was used to identify QTLs for the body weight traits. Two significant QTLs for growth were identified on chicken chromosome 3 (GGA3) for growth 16 to18 weeks (logarithm of the odds [LOD] = 3.24, Nominal p value = 0.0001) and GGA4 for growth 6 to 8 weeks (LOD = 2.88, Nominal p value = 0.0003). Additionally, one significant QTL and three suggestive QTLs were detected for body weight traits in KNC; significant QTL for body weight at 4 weeks (LOD = 2.52, nominal p value = 0.0007) and suggestive QTL for 8 weeks (LOD = 1.96, Nominal p value = 0.0027) were detected on GGA4; QTLs were also detected for two different body weight traits: body weight at 16 weeks on GGA3 and body weight at 18 weeks on GGA19. Additionally, two suggestive QTLs for carcass weight were detected at 0 and 70 cM on GGA19. In conclusion, the current study identified several significant and suggestive QTLs that affect growth related traits in a unique resource pedigree in purebred KNC. This information will contribute to improving the body weight traits in native chicken breeds, especially for the Asian native chicken breeds.

FABP3 and FABP4 Genes Are the Potential Candidates for Body Weights in Korean Native Chicken

FABPs, 15 kDa organic substances, are small intracellular proteins which have a primary role to regulate fatty acid uptake and intracellular transport. This study was conducted to identify SNPs in the two FABP family genes and their associations with the body weight traits in Korean native chicken (KNC). Two SNPs, namely g.508C>T of FABP3 gene and g.285C>T of FABP4 gene, have been genotyped by using PCR-RFLP method. The results showed that FABP3 was significantly associated with body weight at birth, body weights at 12 to 20 weeks, and also slaughter weight. Moreover, the g.285C>T SNP of FABP4 gene was not associated with any body weight traits. These results suggested that the g.508C>T SNP of FABP3 genes can be used as molecular markers to select KNC having desirable body weights.