Nu Ri Choi

Discrimination of the commercial Korean native chicken population using microsatellite markers

BackgroundKorean native chicken (KNC) is a well-known breed due to its superior meat taste. This breed, however, owing to a low growth rate, has a high market price. In order to overcome this disadvantage, the National Institute of Animal Science (NIAS) in Korea developed a commercial KNC breed, named Woorimatdag version 2 (WM2), an upgraded version of the Woorimatdag (WM1) breed and the WM2 was created by crossing the KNC with meat type breeds. This study aims to discriminate between WM2 and other chicken breeds using microsatellite (MS) markers.MethodsA total of 302 individuals from eight Korean chicken populations were examined. The genetic diversity and population structure analysis were investigated using Cervus, API-CALC, STRUCTURE, PowerMarker programs.ResultsBased on heterozygosity and polymorphic information content (PIC) values, 30 MS markers were initially selected from 150 markers. The identified average number of alleles (Na), expected heterozygosity, and PIC values for the WM2 samples were 7.17, 0.741, and 0.682, respectively. Additionally, the paternity of individuals was assigned with a success rate of greater than 99% using 12 markers, the best minimum number of markers. The 12 selected markers contained heterozygosity and PIC values above 0.7 and probability of identity values around zero. Using these markers, the determined probability of identity (PI), PIhalf-sibs, and PIsibs values were 3.23E-33, 5.03E-22, and 8.61E-08, respectively.ConclusionsWM2 is well differentiated with respect to other chicken breeds based on estimated genetic distances. The results presented here will contribute to the identification of commercial WM2 chicken in the market.

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.

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.

Phylogenetic Analysis using mtDNA D-loop Sequences in Korean Native Ducks

Poultry Science Division, National Institute of Animal Science, RDA, Cheonan 331-801, KoreaABSTRACT Recently, the consumption of duck meat has been gradually increased in Korea. However, most of the duck breeds in Korea were imported from overseas. Based on the large demands for the breeding stocks of native ducks, a new project for the commercial use of the Korean native ducks has been launched. For the initial investigation of the relationships between Korean native duck (KND) with other duck breeds, the sequences from D-loop control region in mitochondrial DNA (mtDNA) was used. The results from phylogenetic analysis indicated that both KND and White Commercial Duck (WCD) breeds were classified well with wild duck breeds. However, mallard duck was not discriminated well with KND. The haplotype analysis indicated that KND and WCD have eight different haplotypes with eleven SNPs. Three haplotypes (haplotype 1, 3, 4) were shared both in KND and WCD. On the other hand, haplotype 1 was appeared only KND and haplotype 5, 6, 7, 8 were identified only in WCD population. With further verifications, the results presented here can be used for the conservation and commercialization of the Korean native ducks.(Key words : D-loop, haplotype, Korean native duck, phylogeny)

Identification of quantitative trait loci for the fatty acid composition in Korean native chicken

Objective Fatty acid composition is one of the most important meat quality traits because it can contribute to functional, sensorial, and nutritional factors. In this study, quantitative trait locus (QTL) analyses for fatty acid composition traits were investigated in thigh and breast meat of Korean native chicken (KNC). Methods In total, 18 fatty acid composition traits were investigated from each meat sample using 83 parents, and 595 F1 chicks of 20 week old. Genotype assessment was performed using 171 informative DNA markers on 26 autosomes. The KNC linkage map was constructed by CRI-MAP software, which calculated genetic distances, with map orders between markers. The half-sib and full-sib QTL analyses were performed using GridQTL and SOLAR programs, respectively. Results In total, 30 QTLs (12 in the thigh and 18 in the breast meat) were detected by the half-sib analysis and 7 QTLs (3 in the thigh and 4 in the breast meat) were identified by the full-sib analysis. Conclusion With further verification of the QTL regions using additional markers and positional candidate gene studies, these results can provide valuable information for determining causative mutations affecting the fatty acid composition of KNC meat. Moreover, these findings may aid in the selection of birds with favorable fatty acid composition traits.

The Line Differences and Genetic Parameters of Linoleic and Arachidonic Acid Contents in Korean Native Chicken Muscles

Poultry Science Division, National Institute of Animal Science, RDA, Seonghwan 330-801, KoreaABSTRACT Korean native chicken (KNC) is classified as five lines (grey, black, red, white, brown) based on the plumage colors. The KNC has superior meat quality and flavor compared with those of the commercial broilers, which can be explained by the high arachidonic acid contents. The current study was conducted to investigate arachidonic acid contents in five lines of KNC and used for the development of commercial KNC. Breast and thigh muscles from 597 F1 KNC birds were used in this study and linoleic (precursor of the arachidonic acid) and arachidonic acid contents were measured by the standard protocol. In addition, heritabilities and genetic correlations were estimated. As the results, arachidonic acid contents were significantly different among the KNC lines. Also, relatively high heritabilities (0.4140.570) for arachidonic acid contents were estimated in both breast and thigh muscles. The estimated genetic correlation was negative between linoleic and arachidonic acids. This study indicated that selection of KNC is possible for improving meat flavor in relation to the arachidonic acid. Also, this study can be used for making breeding plans for commercial KNC in the future.(Key words : arachidonic acid, linoleic acid, meat flavor, Korean native chicken)