Y chromosomal deletion pattern in Koreans inhabiting Jeju Island.

ABSTRACT: Mutations occur in Y chromosome genes similar to autosomal genes. However, unlike autosomal genes, Y chromosome genes do not undergo recombination, which produce distinctive characteristics and distribution patterns in different geographic regions. Therefore, detailed analysis of mutations of Y chromosome genes might provide information for personal identification or analysis of phylogenetic history. In Y-STR (short tandem repeat) analysis tests on 668 habitants of Jeju Island, the largest island in the Korean peninsula located apart from the mainland, a deletion at DYS448 was found in 10 samples. The length of deletion was estimated by confirming specific Sequence Tagged Site (STS) markers ranging from G66018 to sY1201. Patterns found were similar to those of the Kalmyks, a tribe that has had strong social and genetic influences in Jeju Island in the past. Historically from 1273 on, Jeju Island was governed by Mongolian for about one hundred years. The results of this study suggest such historical aspects affected the genetic composition of people living in Jeju Island. Furthermore, previous reports showed that Y chromosomal deletions and region specific Y chromosomal mutations depended on regional differences. This study may be useful for a better understanding of the genetic structure of Jeju habitants as well as Korean population for the purpose of forensic practice and population genetics.

Improvement of short tandem repeat analysis of samples highly contaminated by humic acid.

We investigated several methods for obtaining successful short tandem repeat (STR) results from high-humic acid (HA)-content samples. DNA purification efficiency was tested for QIAquick(®) PCR Purification, QIAamp(®) DNA Investigator and Prepfiler™ Forensic DNA Extraction kits. HA-removal capacity of Inhibitor Remover and InhibitEX(®) Tablet was tested. Experiments on overcoming HA effects on STR amplification were conducted using an AmpliTaq Gold(®) DNA Polymerase and a TaKaRa Ex Taq™ Hot Start Version (Ex Taq HS) with BSA addition. QIAquick kit was most efficient in HA removal and Ex Taq HS showed high resistance to HA. Increasing the amounts of Taq polymerases and BSA addition were shown to be efficient in overcoming PCR inhibition, but BSA addition was superior to the former method. Inhibitor Remover and InhibitEX(®) Tablet did not positively affect the STR results. This study will help achieve better STR results with high-HA-content samples.