Network


Latest external collaboration on country level. Dive into details by clicking on the dots.

Hotspot


Dive into the research topics where Koji Dewa is active.

Publication


Featured researches published by Koji Dewa.


International Journal of Legal Medicine | 2007

Y-chromosomal microsatellite mutation rates in a population sample from northwestern Germany.

Carsten Hohoff; Koji Dewa; Ulla Sibbing; Karolin Hoppe; Peter Forster

To estimate Y-chromosomal short tandem repeat (Y-STR) mutation rates, 15 loci (i.e., DYS19, DYS389 I/II, DYS390, and DYS393; DYS437, DYS438, DYS439, and DYS385; DYS391, DYS392, YCA II, and DXYS156) were analyzed in a sample of 1,029 father/son pairs from Westphalia, northwestern Germany. Among 15,435 meiotic allele transfers, 32 mutations were observed; thus, the mutation rate across all 15 Y-STR loci was 2.1 × 10−3 per locus (95% C.I.: 1.5–3.0 × 10−3). With the exception of a three-repeat mutation at DYS385, all remaining mutations were single repeat mutations. Repeat losses were more frequent than gains (20:12), and the mutation rate appeared to increase with age. The Y haplogroups that were detected in the individuals showing a mutation reflect the haplogroup distribution in the Westphalian population. Additionally, the correlation of surnames and haplotypes was tested: Only 49 surnames occurred more than once, and only two men with the same rare surname shared the same haplotype. All other men with identical surnames carried different haplotypes.


Journal of Forensic Sciences | 1994

Sex Typing of Forensic DNA Samples Using Male- and Female-Specific Probes

Emiko Naito; Koji Dewa; Haruo Yamanouchi; Ryo Kominami

Forensic DNA samples have been examined to ascertain the feasibility of a sex-typing procedure that we have recently developed. This uses two sets of primers complementary to the DXZ4 and SRY genes for polymerase chain reaction (PCR). PCR target in the DXZ4, an 80-bp sequence within the 130-bp fragment specific to females, is generated from inactive chromosome X by the DNA digestion with a methylation-sensitive restriction enzyme, HpaII. Therefore, the DXZ4 amplification and subsequent agarose gel electrophoresis detect the 80-bp fragment from female DNA. On the other hand, the SRY probe identifies a male-specific sequence on chromosome Y. Testing DNAs from fresh Turners blood and from postmortem tissues exhibited band-signals confirming the sex identification. Degraded DNAs isolated from severely decomposed specimens were also identifiable when high-molecular-weight DNA was isolated before the assay. This demonstrates the usefulness of this method in forensic identification.


International Congress Series | 2003

Analysis of 13 Y-chromosomal STRs in an Arab population sample from Syria

Louai Abdin; Koji Dewa; Steven Rand; Carsten Hohoff; B. Brinkmann

Abstract Analysis of Y-chromosomal STRs has become increasingly important for forensic and population genetics. Although many populations have already been analysed, there are only few data on Arabic populations. A total of 13 polymorphic STR loci on the Y-chromosome were analysed in a Syrian population sample of 113 unrelated males (the majority from Lattakia) and 108 different haplotypes were observed, 104 haplotypes of them were found to be unique and the others were shared by two or three persons. The haplotype diversity was 0.9902.


International Congress Series | 2003

13 Y-chromosomal STRs in a Vietnamese population

Koji Dewa; Nguyen Quang Tuyen; Steven Rand; Carsten Hohoff; B. Brinkmann

We present the frequency distributions of 13 Y-specific STR polymorphisms (DYS19, DXYS156, DYS385, DYS389 I and II, DYS390, DYS391, DYS392, DYS393, DYS437, DYS438, DYS439 and YCAII) and the frequency of the combination of these haplotypes in Vietnamese males. D 2003 Elsevier Science B.V. All rights reserved.


International Journal of Legal Medicine | 2001

A novel dimorphism in the human SRY gene: usefulness in human migration studies.

Emiko Naito; Kazuo Umetsu; Isao Yuasa; Koji Dewa; Hirokazu Sumi; Haruo Yamanouchi

Abstract A nucleotide polymorphism of C or T was detected at position 465 in the sex-determining region Y (SRY) gene. To evaluate the utility of this dimorphism in human population studies, the frequency and the frequency of the haplotype combined with the two polymorphic loci YAP and M9 were examined in a total of 130 unrelated Japanese and 130 unrelated German males. The T nucleotide was found in 24.6% (32/130) of the Japanese but not in any of the 130 German males. Accordingly, four of the eight possible combination haplotypes of SRY/YAP/M9 were identified in the Japanese population, but one of the four haplotypes comprising SRY(T) was absent in the German samples. This suggests that the C to T transition may be more recent than the YAP insertion or the M9 transversion and the change might have occurred in an ancestral Asian population. These results imply that the dimorphism at the SRY gene is one of the Y-linked markers useful for human population studies and also for ethnic identification of forensic samples.


International Congress Series | 2003

A VNTR polymorphism in human 5′ H19 flanking regions in Japanese and German populations

Masaaki Fukuda; Emiko Naito; Koji Dewa; Kazuo Umetsu; Isao Yuasa; Haruo Yamanouchi

In mammals, imprinted genes are preferentially expressed from either the maternal or paternal allele. Several recent observations show that DNA methylation plays an important role in the imprinted inheritance of the gene. Generally, an individual inherits two alleles together from his parents and the origin of each allele can be determined by typing the parents. The ultimate aim of this study is to detect a paternally or maternally derived allele from one person by using the methylation difference in the imprinted region. For the purpose, a useful probe within the region is requisite as the analytic target. In this study, the forensic utility of the VNTR locus, which is located approximately 7.6 kb upstream of the H19 gene that is maternally expressed, was evaluated. The human 5VH19 flanking sequence was searched from the DDBJ. The allele frequency of the VNTR locus was examined in a total of 199 unrelated Japanese and 171 unrelated German individuals. In the Japanese samples, 7 alleles and 22 genotypes were identified. The heterozygosity and polymorphism information content (PIC) were 0.749 and 0.669, respectively. By contrast, 9 alleles and 27 genotypes were detected in the German samples. The heterozygosity and PIC were 0.969 and 0.705, respectively. Thus, the frequency distribution of the two populations showed different profiles (Table 1). In a Japanese case study, this genetic typing was successfully applied to the personal identification of decomposed remains as a forensic sample. These results indicated that the VNTR in the H19-5Vflanking region is highly polymorphic and useful for personal identification of both Japanese and German DNA samples. This suggests the VNTR has become a useful probe for the aimed method.


Legal Medicine | 2019

A quantitative morphological analysis of three-dimensional CT coxal bone images of contemporary Japanese using homologous models for sex and age estimation

Hitoshi Biwasaka; Yasuhiro Aoki; Yusuke Takahashi; Mamiko Fukuta; Akihito Usui; Yoshiyuki Hosokai; Haruo Saito; Masato Funayama; Sachiko Fujita; Masataka Takamiya; Koji Dewa

Sexual dimorphisms and age-dependent morphological features of the human coxal bone were quantitatively analyzed using homologous models created from three-dimensional (3D) computed tomography images of the pelvis (male: 514 samples, female: 388 samples, age 16-100). Bilateral average coxal images of each sex and age decade were generated separately through principle component analyses (PCA). By measuring average point-to-point distances of 8472 corresponding points (average corresponding point differences [ACPDs]) between each homologous coxal image and the average images, the sex of more than 93% of the samples was correctly assigned. Some principal components (PCs) detected in PCA of the homologous models of the samples correlated fairly well with age and are affected by features of the curvature of the iliac crest, the arcuate line and the greater sciatic notch. Moreover, separate PCA using the average images of each age decade successfully detected the first PCs, which were strongly correlated with age. However, neither multiple regression analysis using PCs related to age nor comparison of ACPDs with the average images of each age decade could produce accurate results for age decade assignment of unknown (blind) samples. Therefore, more detailed analysis of age-dependent morphological features would be necessary for actual age estimation. In addition, some laterality or left and right shape difference of the coxal bone images was also elucidated, and was more significant in females. Analysis of 3D structures using homologous models and PCA appears to be a potential technique to detect subsistent morphological changes of bones.


Journal of Forensic Science & Criminology | 2014

Programming Scripts for Simple and Complex Paternity Testing based on Open-Source Programming Language from the R Project

Masataka Takamiya; Yasuhiro Aoki; Koji Dewa

Programming scripts were written for the statistical analysis of genetic data from simple cases and complex cases of undetermined paternity. The methods presented here involve algorithms constructed with R, an open-source and increasingly popular programming language used for calculations and statistics; these methods also involve conditional probability analysis, Bayes’ Theorem, and pedigree analysis. Previous computer programs for assessing probable paternity in complex cases of undetermined paternity have been written; however, only minimal or generalized formulas are described in the papers presenting these programs. Therefore, these previously published programs are difficult to understand for most forensic researchers. Here, we present the details of the calculations used to evaluate probabilities of paternity and the details of the R scripts used execute these calculations. These scripts were constructed not only for standard trio case where DNA typing of the mother, child, and the alleged father are available, but also for more complex cases where DNA typing of the alleged father is absent. In these more complex cases, the putative genotype of the alleged father is determined from the genotypes of his parents, his siblings, his wife, children known to be his biological children, or some combination of these people. This report provides concrete and orderly descriptions of the calculations and the R scripts so that each facet of this method is easily understood. Furthermore, access to these scripts will enable individual researchers to develop calculation systems of their own.


Journal of Forensic Sciences | 2003

Novel paternity testing by distinguishing parental alleles at a VNTR locus in the differentially methylated region upstream of the human H19 gene.

Emiko Naito; Koji Dewa; Masaaki Fukuda; Hirokazu Sumi; Yuichi Wakabayashi; Kazuo Umetsu; Isao Yuasa; Haruo Yamanouchi


Marine Mammal Science | 2001

PRACTICAL USE OF MULTIPLEX FLUORESCENT PCR FOR CETACEAN SEX IDENTIFICATION

Hideaki Abe; Mutsuo Goto; Luis A. Pastene; Koji Dewa; Emiko Naito

Collaboration


Dive into the Koji Dewa's collaboration.

Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Researchain Logo
Decentralizing Knowledge