Genetic traceability of black pig meats using microsatellite markers

Abstract

Pork from Jeju black pig (population J) and Berkshire (population B) has a unique market share in Korea because of their high meat quality. Due to the high demand of this pork, traceability of the pork to its origin is becoming an important part of the consumer demand. To examine the feasibility of such a system, we aim to provide basic genetic information of the two black pig populations and assess the possibility of genetically distinguishing between the two breeds. Muscle samples were collected from slaughter houses in Jeju Island and Namwon, Chonbuk province, Korea, for populations J and B, respectively. In total 800 Jeju black pigs and 351 Berkshires were genotyped at thirteen microsatellite (MS) markers. Analyses on the genetic diversity of the two populations were carried out in the programs MS toolkit and FSTAT. The population structure of the two breeds was determined by a Bayesian clustering method implemented in structure and by a phylogenetic analysis in Phylip. Population J exhibited higher mean number of alleles, expected heterozygosity and observed heterozygosity value, and polymorphism information content, compared to population B. The FIS values of population J and population B were 0.03 and -0.005, respectively, indicating that little or no inbreeding has occurred. In addition, genetic structure analysis revealed the possibility of gene flow from population B to population J. The expected probability of identify value of the 13 MS markers was 9.87×10(-14) in population J, 3.17×10(-9) in population B, and 1.03×10(-12) in the two populations. The results of this study are useful in distinguishing between the two black pig breeds and can be used as a foundation for further development of DNA markers.

Keywords: Black Pig Populations; Genetic Traceability; Heterozygosity; Microsatellite Markers; Probability of Identity.

Figure 1

A neighbor joining dendrogram was constructed from allele-sharing distances among 400 individuals in the two pig populations. J: Jeju black pigs, B: Berkshire pigs.

Figure 2

Clustering assignment of the two pig populations obtained by structure analyses. Each of the 400 animals is represented by a thin vertical line that is divided into segments whose size and color correspond to the relative proportion of the animal genome corresponding to a particular cluster. Panel with K = 2 inferred clusters, J (Jeju black pigs) and B (Berkshire) populations are discriminated.