Population genetic study of 10 short tandem repeat loci from 600 domestic dogs in Korea

Dogs have long shared close relationships with many humans. Due to the large number of dogs in human populations, they are often involved in crimes. Occasionally, canine biological evidence such as saliva, bloodstains and hairs can be found at crime scenes. Accordingly, canine DNA can be used as forensic evidence. The use of short tandem repeat (STR) loci from biological evidence is valuable for forensic investigations. In Korea, canine STR profiling-related crimes are being successfully analyzed, leading to diverse crimes such as animal cruelty, dog-attacks, murder, robbery, and missing and abandoned dogs being solved. However, the probability of random DNA profile matches cannot be analyzed because of a lack of canine STR data. Therefore, in this study, 10 STR loci were analyzed in 600 dogs in Korea (344 dogs belonging to 30 different purebreds and 256 crossbred dogs) to estimate canine forensic genetic parameters. Among purebred dogs, a separate statistical analysis was conducted for five major subgroups, 97 Maltese, 47 Poodles, 31 Shih Tzus, 32 Yorkshire Terriers, and 25 Pomeranians. Allele frequencies, expected (Hexp) and observed heterozygosity (Hobs), fixation index (F), probability of identity (P(ID)), probability of sibling identity (P(ID)(sib)) and probability of exclusion (PE) were then calculated. The Hexp values ranged from 0.901 (PEZ12) to 0.634 (FHC2079), while the P(ID)(sib) values were between 0.481 (FHC2079) and 0.304 (PEZ12) and the P(ID)(sib) was about 3.35 × 10⁻⁵ for the combination of all 10 loci. The results presented herein will strengthen the value of canine DNA to solving dog-related crimes.

DNA Database Searching Using Genetic Relationship / 대한법의학회지

The usefulness of DNA databases is well known. In Korea, many cases have been solved since the establishment of DNA databases in 2010. DNA profiles obtained from criminal evidence are analyzed and are kept in databases, and matching profile is searched. On the matching occasion, DNA databases can provide some investigative information. Close family members, for example father, son or brother, share more alleles than unrelated people. This genetic closeness can be searched using the so called familial searching, and many successful cases have been reported. Management of DNA databases including familial searching needs continuous monitoring and control, especially from ethical view points. Many different views for familial searching have been presented, and each country running DNA databases has their own different policies. We present the utility, approaches and different policies of familial searching as well as arguments for and against familial searching. We also suggest that our appropriate guidelines be mandatory and a proper administrative process be prepared for the start of familial searching.

Application of Differex(TM) system and FTA(R) technology to separation of sperm DNA from mixed stains / 대한법의학회지

Specimens from sexual crimes are generally mixed stains consisted of sperm cells(from suspect) and virginal cells(from victim). We have combined two new methods - Differex(TM) system and FTA(R) technology- to overcome shortcomings of method that has been used before to separate sperm DNA from mixed stains. This methods have shown additional benefits and similar quality than using the only Differex(TM) system to the experiment. The result of our experiment represents the possibility that Differex(TM) system and FTA(R) technology would be useful methods for DNA analysis related to sexual crimes because this system can save time, labor and contamination for experiments.

Population Study of Y-chromosome STR Haplotypes in Koreans / 대한법의학회지

The Y-chromosome short tandem repeat (STR) systems including DYS391, DYS389I/II, DYS439, DYS438, DYS437, DYS19, DYS392, DYS393, DYS390 and DYS385 (PowerPlex Y System, Promega) were investigated in 569 Korean males (the Central region). A total of 473 haplotypes were observed in the 569 individuals studied, of which 426 (90.06%) were unique. The overall haplotype diversity for the 12 Y-STR loci was 0.9985, and the discrimination capacity was 0.8313. The gene diversity varied from 0.2586 at DYS391 to 0.9558 at DYS385. We scrutinized for the presence of non-standard (intermediate and duplicated) alleles among Y chromosome STR haplotypes. Three mutations were identified in three short tandem repeat (STR) loci DYS439, DYS19 and DYS385. In DYS439, we found a new mutant allele that added an A at upstream of the first GATA motif of the repeat region. The allele was designated 11.1 according to the sequence structure. We also detected a duplicate allele in DYS19 and a triplicate allele at DYS385 locus.

Comparison of parentage testing results from several institutes in Korea / 대한법의학회지

Collaborative work using same samples for the parentage testing, which was intended to see the status and the quality of several DNA typing laboratories in Korea, was described. Samples were consisted of two sets, one was a trio case and the other was a deficient case with two children. Samples were sent to six laboratories, among which five submitted the result. Each laboratory had used different number and set of STR loci using 14 - 23 loci, and total 33 different loci were used. Only one VNTR locus, D1S80 was included and all the remaining were STR loci. The loci included in the commercial kits were used more frequently. One laboratory had used Korean-made commercial kits. All the laboratories gave the same results about the parentage, although results for one locus were not the same through different laboratories. There existed minor difference in the PI calculation, especially in the statistical parameters such as allelic frequences, which might gave confusion to users of the results who were not familiar with the test. Necessity about the standardization and profiling data were discussed.

Comparison of STR Typing Results from Several Centers for the Same Samples: Steps to Standardization for STR Typing / 대한법의학회지

This paper described a collaborative exercise intended to see what kinds of short tandem repeat (STR) loci are used in different DNA typing laboratories in Korea and to compare their results for the demonstration whether uniformity of DNA profiling results from different laboratory could be achieved in Korea. Laboratories were asked to test five tissue DNAs using methods routinely used in each laboratory and to report the results to the coordinating laboratory. The exercise demonstrated that each laboratory was using different STR loci for the typing with different STR numbers, 2 VNTRs, 36 STRs and amelogenin in total, and the direct comparison of the results from all the laboratory for the 18 loci could not be done as only one laboratory submitted typing results. Among 21 loci for which several laboratories submitted typing results, results for 14 loci were the same and results for the other 7 loci were different depending on the participating laboratory. D1S80, F13A01, D16S539, D21S11, D18S51, D3S1744 were the loci with different typing results. Even in the cases where commercial kits were used, the results were not the same depending on the machines used, that is the capillary electrophoresis or the gel based electrophoresis. The reason for the different results, points about the standardization of the methods and the profiling data were described.

Comparison of STR Typing Results from Several Centers for the Same Samples: Steps to Standardization for STR Typing / 대한법의학회지

This paper described a collaborative exercise intended to see what kinds of short tandem repeat (STR) loci are used in different DNA typing laboratories in Korea and to compare their results for the demonstration whether uniformity of DNA profiling results from different laboratory could be achieved in Korea. Laboratories were asked to test five tissue DNAs using methods routinely used in each laboratory and to report the results to the coordinating laboratory. The exercise demonstrated that each laboratory was using different STR loci for the typing with different STR numbers, 2 VNTRs, 36 STRs and amelogenin in total, and the direct comparison of the results from all the laboratory for the 18 loci could not be done as only one laboratory submitted typing results. Among 21 loci for which several laboratories submitted typing results, results for 14 loci were the same and results for the other 7 loci were different depending on the participating laboratory. D1S80, F13A01, D16S539, D21S11, D18S51, D3S1744 were the loci with different typing results. Even in the cases where commercial kits were used, the results were not the same depending on the machines used, that is the capillary electrophoresis or the gel based electrophoresis. The reason for the different results, points about the standardization of the methods and the profiling data were described.

The Disaster Victim Identification using DNA Typing

Disaster victim identification traditionally relies on the combined efforts of police, dentists and pathologists, comparing ante motem(AM) information from the missing persons with posts mortem(PM) data from the dead bodies. Victim identification by DNA typing was then followed by comparisons of traditional AM and PM data. DNA typing is a useful tool for determining the identity of human remains. However, the DNA, extracted from the human remains - all tissue including blood, semen, hair follicles, bone and soft tissue - is often partially or severely degraded. Samples containing limited amounts of degraded DNA are more suitable for analysis by DNA-amplification methods. DNA-amplification by polymerase chain reaction (PCR) was first described 10 years ago, PCR has significantly extended the possibilities of DNA typing of human remains. But DNA analysis, which is far more expensive and time-consuming than conventional means of identifying human remains, is not likely to become the primary tool for identifications in aviation disasters.