Development of a 30 Y-STR Loci with middle or low mutations multiplex PCR system / 中国法医学杂志

Objective To deveplope construct and validate a novel multiplex PCR system comprised of 30 Y-STR markers only with low and moderate mutation rates. Methods 30 Y-STRs characterized by low/moderate mutation rate and middle/high polymorphic was amplified simultaneously in a multiplex PCR system using the six color labeling fluorescence. PCR product was analyzed in a ABI 3500XL Genetic Analyzer. The accuracy, specifity, sensitivity and stability of the system and its validation on the mixtures were evaluated. Results The validation studies demonstrated that the system is a stable, accurate, and sensitive multiplex PCR system. The sensitivity was 0.0625ng DNA. Y-STR could be detection in a male/female DNA mixture ratio of 1:4. Conclusion The primary study demonstrates that this multiplex PCR system is effective and reliable for forensic routine DNA analysis. It will be very helpful for constructing Chinese forensic Y-STR database and population genetic research.

Haplotype and genetic relationship of 27 Y-STR loci in Han population of Chaoshan area of China / 解放军医学杂志

Objective To investigate the genetic polymorphisms of 27 Y-chromosomal short tandem repeats (Y-STR) loci included in Yfiler(R) Plus kit in Han population of Chaoshan area,and explore the population genetic relationships and evaluate its application value on forensic medicine.Methods By detecting 795 unrelated Chaoshan Han males with Yfiler(R) Plus kit,haplotype frequencies and population genetics parameters of the 27 Y-STR loci were statistically analyzed and compared with available data of other populations from different races and regions for analyzing the genetic distance and clustering relation of Chaoshan Han population.Results Seven hundred and eighty-seven different haplotypes were observed in 795 unrelated male individuals,of which 779 haplotypes were unique,and 8 haplotypes occurred twice.The haplotype diversity (HD) was 0.999975 with discriminative capacity (DC) of 98.99％.The gene diversity (GD) at the 27 Y-STR loci ranged from 0.3637(DYS391) to 0.9559(DYS385a/b).Comparing with Asian reference populations,the genetic distance (Rst) between Chaoshan Han and Guangdong Han was the smallest (0.0036),while it was relatively larger between Chaoshan Han and Gansu Tibetan population (0.0935).The multi-dimensional scaling (MDS) plot based on Rst values was similar to the results of clustering analysis.Conclusion Multiplex detection of the 27 Y-STR loci reveals a highly polymorphic genetic distribution in Chaoshan Han population,which demonstrates the important significance of Yfiler(R) Plus kit for establishing a Y-STR database,studying population genetics,and for good practice in forensic medicine.

Asian Ethnic Group Classification Model Using Data Mining / 대한법의학회지

In addition to identifying genetic differences between target populations, it is also important to determine the impact of genetic differences with regard to the respective target populations. In recent years, there has been an increasing number of cases where this approach is needed, and thus various statistical methods must be considered. In this study, genetic data from populations of Southeast and Southwest Asia were collected, and several statistical approaches were evaluated on the Y-chromosome short tandem repeat data. In order to develop a more accurate and practical classification model, we applied gradient boosting and ensemble techniques. To infer between the Southeast and Southwest Asian populations, the overall performance of the classification models was better than that of the decision trees and regression models used in the past. In conclusion, this study suggests that additional statistical approaches, such as data mining techniques, could provide more useful interpretations for forensic analyses. These trials are expected to be the basis for further studies extending from target regions to the entire continent of Asia as well as the use of additional genes such as mitochondrial genes.

Detection of Y Chromosomal Microdeletions in Patients with Spermatogenic Failure / 中国医科大学学报

Objective To explore the relationship between Y chromosomal microdeletions and chromosome karyotype,clinical phenotypes and sex hormone levels in patients with spermatogenic failure.Methods SRY gene,ZFY gene and 6 sequence-tagged-sites in AZFa,AZFb and AZFc were detected with multiplex polymerase chain reaction in 42 non-obstructive azoospermic and 39 severe oligozoospermic men.Results Ten cases (12.35%) of microdeletions were found in 81 non-obstructive azoospermic (6 cases) or severe oligozoospermic patients (4 cases).Among the 10 patients with Y chromosomal microdeletions, 1 had deletion of AZFa+AZFb+AZFc,2 AZFb+AZFc, 1 AZFb and 6 AZFc.Conclusion Microdeletions in the long arm of Y chromosome were associated with spermatogenic failure.Screening for Y chromosomal microdeletions in azoospermic or severe oligozoospermic patients should be of necessity and significance.

Identification of Y Chromosomal Material in Turner Syndrome by Fluorescence In Situ Hybridisation (FISH)

Turner syndrome is one of the most common chromosomal abnormalities affecting newborn females. More than half of patients with Turner syndrome have a 45X karyotype. The rest of the patients may have structurally abnormal sex chromosomes or are mosaics with normal or abnormal sex chromosomes. Mosaicism with a second X sex chromosome is not usually of clinical significance. However, Turner syndrome patients having a second Y chromosome or Y chromosomal material are at risk of developing gonadoblastoma later in life. The aim of this study is to compare the results of conventional (karyotyping) and molecular cytogenetics (FISH), and discuss the advantages and limitations in the diagnosis of Turner syndrome. We also aim to compare the degree of mosaicism identified using conventional cytogenetics and FISH techniques. Conventional cytogenetics and FISH analyses were performed on eight peripheral blood samples of patients with Turner syndrome collected between 2004 and 2006. From this study, two out of eight patients with Turner syndrome were found to have the sex determining region on the Y chromosome (SRY) gene by FISH analysis. Our results showed that the rate of detection of mosaic cases in Turner syndrome was also increased to 88% after using the FISH technique. We concluded that FISH is more superior to conventional cytogenetics in the detection of the Y chromosomal material. FISH is also a quick and cost effective method in diagnosing Turner syndrome and assessing the degree of mosaicism.