Ji-Eun Yoo

Mitochondrial DNA control region sequences in Koreans: identification of useful variable sites and phylogenetic analysis for mtDNA data quality control

We have established a high-quality mtDNA control region sequence database for Koreans. To identify polymorphic sites and to determine their frequencies and haplotype frequencies, the complete mtDNA control region was sequenced in 593 Koreans, and major length variants of poly-cytosine tracts in HV2 and HV3 were determined in length heteroplasmic individuals by PCR analysis using fluorescence-labeled primers. Sequence comparison showed that 494 haplotypes defined by 285 variable sites were found when the major poly-cytosine tract genotypes were considered in distinguishing haplotypes, whereas 441 haplotypes were found when the poly-cytosine tracts were ignored. Statistical parameters indicated that analysis of partial mtDNA control region which encompasses the extended regions of HV1 and HV2, CA dinucleotide repeats in HV3 and nucleotide position 16497, 16519, 456, 489 and 499 (HV1ex+HV2ex+HV3CA+5SNPs) and the analysis of another partial mtDNA control region including extended regions of HV1 and HV2, HV3 region and nucleotide position 16497 and 16519 (HV1ex+HV2ex+HV3+2SNPs) can be used as efficient alternatives for the analysis of the entire mtDNA control region in Koreans. Also, we collated the basic informative SNPs, suggested the important mutation motifs for the assignment of East Asian haplogroups, and classified 592 Korean mtDNAs (99.8%) into various East Asian haplogroups or sub-haplogroups. Haplogroup-directed database comparisons confirmed the absence of any major systematic errors in our data, e.g., a mix-up of site designations, base shifts or mistypings.

Five highly informative X-chromosomal STRs in Koreans

The five X-chromosomal short tandem repeats (STRs) GATA172D05, HPRTB, DXS8377, DXS101 and HumARA were analyzed in 150 males and 150 females from Korea. Markers were amplified in a quadruplex and a monoplex PCR reaction with fluorescently labeled primers. For accurate and reproducible STR typing, sequenced allelic ladders were constructed and a Genotyper macro was programmed. Some differences were found on comparing the allele frequencies of Koreans with those of other populations in DXS8377, DXS101 and HumARA. The forensic efficiency parameters showed that the five X-linked STRs are highly informative for forensic application in Koreans.

Mitochondrial DNA CA dinucleotide repeats in Koreans: the presence of length heteroplasmy

The mitochondrial DNA HV3 region contains CA dinucleotide repeats which display length polymorphism. To analyze this for forensic purposes, we designed a fluorescence-labelled PCR primer set for short amplification products and carried out genotyping by using capillary electrophoresis. A total of 4 alleles with 4–7 repeat units were observed and the genetic diversity was estimated to be 0.5120 in 500 unrelated Koreans. Interestingly, three individuals showed two or three length variants, i.e. length heteroplasmy.

Differential Distribution of Human Mitochondrial DNA in Somatic Tissues and Hairs

To investigate mitochondrial DNA (mtDNA) distribution within tissues during life, we observed length heteroplasmy in a polycytosine tract of the mitochondrial HV2 region by size‐based separation of PCR products, using a mutagenic primer which was designed to avoid stutter production. Blood, brain, heart, liver, skeletal muscle and hair shaft samples were collected during autopsies of 25 individuals. Here, we demonstrate differences in the level of mtDNA length heteroplasmy both within and between individuals and tissues. We also show that mtDNA is distributed randomly in varying proportions in various somatic tissues during growth, resulting in an imbalance in the composition of mtDNA pools among tissues. This mtDNA distribution appears not to be strictly random, and can be explained by the random somatic segregation of nucleoids. On the other hand, significant qualitative/quantitative mtDNA peak pattern variations in hair shafts are thought to be a result of the different developmental origins of hairs. Each hair shaft may have a restricted or clonal set of mtDNA molecules derived from a discrete group of stem cells.

Protective Informal Social Control of Child Maltreatment and Child Abuse Injury in Seoul

Previous findings on the relationship between neighborhood informal social control and child abuse have been mixed. We implemented a scale created by Emery, Trung, and Wu to study protective informal social control of child maltreatment (ISC_CM) by neighbors in a three-stage random cluster sample of 541 families in Seoul, South Korea. Random-effects regression models found that protective ISC_CM significantly moderated the relationship between very severe abuse and child injuries. Very severe abuse was associated with fewer injuries when levels of protective ISC_CM were higher. Implications are discussed.

Genetic Characterization and Assessment of Authenticity of Ancient Korean Skeletal Remains

Abstract To study the maternal lineage history of Korea, we extracted DNA from the skeletal remains of 35 museum samples (some dating back to the Paleolithic Age) excavated from 11 local burial sites scattered throughout southern Korea. Mitochondrial DNA (mtDNA) control region sequences (HV1, HV2, and HV3) were successfully determined for 11 samples with no sharing of the control region polymorphisms with individuals involved in the laboratory analyses. Each of the 11 mtDNAs was assigned to the appropriate East Asian mtDNA haplogroup according to the haplogroup-specific control region mutation motif and diagnostic coding region single nucleotide polymorphism. The successful mtDNA haplogroup determination for each ancient Korean mtDNA and the confirmation of the absence of abnormal mutations based on the haplogroup-directed database comparisons indicates that there is no mosaic structure from cross-contamination or sample mix-up or other errors in our mtDNA sequences. The presence of haplogroups B, D, and G in the prehistoric age is consistent with the hypothesis that the early Korean population has a common origin in the northern regions of the Altai Mountains and Lake Baikal of southeastern Siberia. In addition, the modern Korean population, which possesses lineages from both southern and northern haplogroups, suggests additional gene flow from southern Asian haplogroups in recent times, but many more ancient samples need to be analyzed to directly tell whether there was regional continuity or replacement of early lineages by other lineages in ancient Korea.

After the Escape: Physical Abuse of Offspring, Posttraumatic Stress Disorder, and the Legacy of Political Violence in the DPRK

What is the relationship between victimization by political violence against women in North Korea and later physical abuse of offspring? This article examines the relationships between victimization by political violence, posttraumatic stress disorder (PTSD), alcohol abuse/dependence, and abuse of offspring after arrival in South Korea. A random sample of 204 female North Korean defectors was used to test hypotheses. An oral history conducted with a survivor of North Korean political violence is provided in an appendix to contextualize the results. Analyses established a significant link between previous victimization by political violence and abuse of offspring but not mediation by either PTSD or alcohol abuse/dependence.