Preliminary study of hair form of Japanese head hairs using image analysis

The use of average curvature measurements for the forensic comparison of curly hairs has been reported, but a method, in which various types of hair form are quantitatively examined and objectively interpreted for hair comparison, has not been reported to date. In the present study, numerical data on hair form from Japanese subjects were obtained by image analysis and a morphological comparison of these head hairs was investigated. Head hairs obtained from eight Japanese males were measured for length (L), distance (D) and area (A) using a Kontron Imaging System KS400. From the three measurements mentioned above, three indexes, L/D, A/D and 2(A/L), were examined. The inter-individual variations for each value were investigated by a t-test and the availability of six values for the forensic comparison of hair form was evaluated by a stepwise linear discrimination analysis. Six values obtained from hair form by an image analysis showed large intra-individual variations. However, these six values were found to be useful for discriminating between two individuals, since the six values showed larger inter-individual variations than intra-individual variations. Discrimination on each comparison using a stepwise linear discrimination analysis was performed for some of the values and the results indicated conspicuous inter-individual variations between the two individuals. On 11 of 28 comparisons, 30 hairs from one individual could be completely distinguished from hairs of another individual, when a two-way comparison was employed. These results confirm that hair form could be quite useful in the forensic comparison of hair morphology, and suggest that numerical data obtained from hair form by image analysis are very important values for constructing a screening procedure for evidential hairs. The use of an objective measure of hair form will be especially useful for Japanese head hairs since they are generally thought to show very limited variation in morphological features.     

The absorption of arsenic into single human head hairs.

Single head hairs from several subjects have been soaked in arsenic radiotracer solution and the arsenic absorbed on 2-mm hair segments has been determined by radioactivity assay. The absorption patterns were characterized for some subjects by regions of high uptake where (in other hairs from the same subject) regions of low uptake of copper and zinc were found, and vice versa. These data have been interpreted in terms of varying densities of binding sites in the hair structure, with specific chemical character. Arsenic absorption patterns for other subjects were highly structured, showing zones of very high and very low absorption. The dangers of interpreting similar patterns for the indigenous arsenic content of hair in terms of the dates on which elevated arsenic ingestion took place have been discussed.     

Forensic mitochondrial DNA analysis of 691 casework hairs

A five year retrospective review of mitochondrial DNA (mtDNA) analysis on 691 casework hairs was carried out. A full or partial mtDNA profile was obtained for > 92% of hairs. With increasing age of the hair, the likelihood of obtaining a full profile decreased, although "mini-primer sets" could often be used to capture a partial profile. With increasing color and diameter of the hair, the likelihood of obtaining a profile increased. Full or partial profiles were obtained on more than 80% of 114 hairs < or = 1.0 cm. Mixtures were observed in 8.7% of hairs tested; mixtures increased with the age of the hair and were presumed to be due to exterior surface contamination that could not be sufficiently cleaned prior to extraction, since the overall level of laboratory contamination was low. The frequency of sequence heteroplasmy was 11.4%, and both hot-spot and novel sites were observed. In about one-third of these observations, another sample in the case showed either the same heteroplasmic site or a nucleotide substitution at that site.     

ABO blood grouping of hairs using an avidin-biotin-peroxidase complex technique

Fifty-nine hair specimens obtained from human autopsies and volunteers were used for the determination of ABO blood group substances using the ABC (Avidin-Biotin Complex) technique. Positive staining for A, B and H blood group substances was detected only in the medulla of the hairs. Blood group antigens could not be detected in seven hair specimens because they possessed no medulla. Forty-seven specimens obtained from fresh cadavers and volunteers gave the correct results corresponding to the blood group of the donor, but some specimens from individuals of blood group A2, Le(a + b-) showed weak reaction with anti-A and strong reaction with anti-H. The staining intensity with anti-B and -H in some individuals of blood group AB was stronger than with anti-A serum. Five hair specimens obtained from decomposed bodies were also examined. The blood group antigens could be specifically detected in hairs obtained from two exhumed and one putrid body, but no positive reactions were obtained from two cases of drowning where the bodies had been in the sea for about 6 months. In a blind trial, hair specimens from 28 individuals were also examined. Twenty-two specimens which possessed a medulla gave the correct result. Six specimens gave no result because they possessed no medulla.     

Statistical comparison of dog and cat guard hairs using numerical morphology

Numerical features obtained from the guard hairs of dogs and cats (total 300 hairs per dog or cat) were statistically compared, in an attempt to discriminate between them. Using hairs from each of five mongrel dogs and cats, eight measurements (length (Len), maximum width (MaxWid), cross sectional maximum diameter, cross sectional minimum diameter, cuticular thickness of the cross section and three scale counts per 100 microm length (observed at three positions: distal third (disSC), middle (midSC) and the proximal third (proSC) portions) and five indexes (hair width index (HWI), medulla index (MI), hair index, cuticle index and the difference in scale counts between the distal and proximal parts (defSC)) were examined. The range for each numerical feature overlapped each other extensively, and none of the features permitted a discrimination between dog and cat hairs, based on the values obtained. However, 12 numerical features, except for the midSC, showed a statistically significant difference between dog and cat hairs, as evidenced by a t-test. For the purpose of comprehensively comparing numerical features and statistically discriminating between dog and cat hairs, a discriminant analysis between the two were carried out using a multiple regression analysis. Four types of discriminant functions produced by combining over five numerical features were examined. Dog and cat hairs could clearly be discriminated using any of the discriminant functions. Species discrimination using the discriminant function permitted the species of a dog or cat to be determined, based on the overall morphologies of various numerical features. When experimentally collected test samples were investigated using the discriminant function using Combination-2, consisting of eight numerical features (Len, MaxWid, MI, HWI, disSC, midSC, proSC and defSC), all 10 cat hairs were correctly determined to be cat hair and 22 of 23 dog hairs were correctly identified. This discriminant function produced good results for species discrimination between dog and cat hairs.     

Microscopical discrimination of human head hairs sharing a mitochondrial haplogroup

In forensic analyses, determining the level of consensus among examiners for hair comparison conclusions and ancestry identifications is important for assessing the scientific validity of microscopical hair examinations. Here, we present data from an interlaboratory study on the accuracy of microscopical hair comparisons among a subset of experienced hair examiners currently analyzing hair in forensic laboratories across the United States. We examined how well microscopical analysis of hair can reliably be used to differentiate hair samples, many of which were macroscopically similar. Using cut hair samples, many sharing similar macroscopic and microscopic features, collected from individuals who share the same mitochondrial haplogroup as an indication of genetic relatedness, we tested multiple aspects that could impact hair comparisons. This research tested the extent to which morphological features related to ancestry and hair length influence conclusions. Microscopical hair examinations yielded accurate assessments of inclusion/exclusion relative to the reference samples among 85% of the pairwise comparisons. We found shorter hairs had reduced levels of accuracy and hairs from populations examiners were not familiar with may have impacted their ability to resolve features. The reliability of ancestry determinations is not yet clear, but we found indications that the existing categories are only somewhat related to current ethnic and genetic variation. Our results provide support for the continued utility of microscopical comparison of hairs within forensic laboratories and to advocate for a combined analytical approach using both microscopical analysis and mtDNA data on all forensic analyses of hair.     

脱落毛发及毛干DNA的STR分型研究

目的探讨脱落毛发及毛干细胞核DNA提取、含量和STR分型问题。方法对脱落毛发或毛干进行DNA提取和定量,使用低扩增体系、增加循环次数和多次平行扩增等方法扩增DNA样本,采用叠加比较的方法分析STR分型。结果15cm脱落毛发样品DNA含量大于0．3ng的样品占52．8％,STR分型成功率为55．6％;15cm毛干样品DNA含量大于0．3ng的样品占30．6％,STR分型成功率为25％。结论采用增加循环次数、多次平行扩增等LCN—STR分型方法和Mini—STR试剂盒有助于脱落毛发及毛千的STR基因座分型获得。     

Morphology of hairs on the head and other parts of the body in the residents of Africa

The morphology of hairs from the head, beard, chest, armpits, and pubis was studied in indigenous population of Sudan, Sierra-Leone, Cote d'Ivoir, Ruanda, Nigeria, Gambia, Kenya, Uganda, Burundi, Zaire, Southern African Republic, Angola, Benin, and Guinea Bissau. A total of 327 hair specimens were examined. A number of new parameters of hairs were determined: thickness, number of cuticle pattern lines per mm, optic edge pattern, cuticle patterns, methods for detecting the cortical and medullar layers, width of hair layers and their transverse sections. The resultant morphological signs are new specific signs for African residents (Negroid) which can be used in forensic medical studies for identifying the race appurtenance of hairs.     

Study of cuticle patterns of head hairs by scanning electron microscopy

Cuticle patterns of 5 subjects living in different countries have been studied under a scanning electron microscope. Hair cuticle pattern in different individuals can be complex, simple, or mixed type. The most incident is the complex type of hair cuticle pattern (75-80%), while the simple type is much more rare (15-20%) and the mixed type still more rare (2-5%). Variation statistical analysis helped differentiate hairs from aborigines of some countries of Asia, Africa, Latin America, and East Europe by the number of cuticle pattern lines. High efficiency of scanning electron microscopy in studies of hair cuticle patterns is shown.     

The use of microscopic postmortem changes in anagen hair roots to associate questioned hairs with known hairs and reconstruct events in two murder cases

In two cases investigated by the New Orleans Police Department Crime Lab, hairs recovered from crime scenes were found to exhibit microscopic postmortem changes in anagen hair roots. These microscopic characteristics were used to associate these hairs with various victims in the cases. In addition to associating questioned hairs with known hairs, the fact that the victims were dead when the hairs were pulled helped investigators reconstruct events in both crimes and corroborate statements made by the arrested subjects in each case.     

Mitochondrial DNA heteroplasmy among hairs from single individuals

A denaturing gradient gel electrophoresis (DGGE) assay was used to detect mitochondrial DNA (mtDNA) sequence heteroplasmy in 160 hairs from each of three individuals. The HV1 and HV2 heteroplasmic positions were then identified by sequencing. In several hairs, the heteroplasmic position was not evident by sequencing and dHPLC separation of the homoduplex/heteroduplex species was carried out with subsequent reamplification and sequencing to identify the site. The overall detection frequency of sequence heteroplasmy in these hairs was 5.8% (28/480) with DGGE and 4.4% (21/280) with sequencing. Sequence heteroplasmy of hair was observed even when the reference blood sample of the individual was homoplasmic. The heteroplasmic positions were not necessarily observed at sites where high rates of substitution have been reported. In two hairs, a complete single base change from the reference blood sample was observed with sequencing, while the heteroplasmic condition at that site in the hair was observed using DGGE. The DGGE results in such samples would serve as an aid in considering the possibility of match significance. In a forensic case, this situation would lead to the possibility of a failure to exclude rather than to be inconclusive.     

Deoxyribonucleic acid (DNA) typing of human leukocyte antigen (HLA)-DQA1 from single hairs in Japanese.

The deoxyribonucleic acid (DNA) typing of human leukocyte antigen (HLA)-DQA1 from single hairs is described. HLA-DQA1 genotypes could be determined from single plucked hair roots. However, it was not easy to type HLA-DQA1 with hair shaft portions. Increase in the specimens of hair shaft portions (over 10 cm in length) to get sufficient DNA caused inhibition of polymerase chain reaction (PCR). Synthetic melanin as well as the one extracted from hairs inhibited the PCR of the genomic DNA template when added to the PCR reaction at the concentrations over than 15 ng/100 microL. Therefore, typability of hair shaft portions seems to depend on the delicate balance of the concentrations of DNA and the contaminated melanin in the final DNA extracts.     

Evaluation and quantification of nuclear DNA from human telogen hairs

Nuclear DNA was extracted from human telogen hairs from 60 individuals. Six to nine hairs from each individual were individually extracted. The amount of DNA recovered from each individual varied greatly, and most samples yielded a quantity of 550 pg or less per hair. A selective extraction buffer was used to remove epithelial cell DNA and the amount of exogenous DNA was determined. DNA was also quantified by real time PCR using three different sized amplicons targeting an Alu sequence. The results were used to determine the state of degradation of the extracted DNA. Different quantities of sample (<100 pg, 100-500 pg, >500 pg) were amplified with the Miniplex kits to determine the minimum DNA template required for successful amplification. DNA recovered from hair showed degradation; however, partial profiles were obtained for those samples containing at least 60 pg using MiniSTRs.     

The evidential value of singed hairs in arson cases

The prevalence of singed hairs on hands was examined in a representative sample comprised primarily of Hamburg LKA staff members to determine the evidential value of such traces in criminal cases. Hair samples were taken from the hands of 160 subjects and examined under a microscope. Evidence of singing was found in 53 of the samples. These traces were largely restricted to a limited number of areas. Distribution of singed hairs over a wide area was observed in just 3 subjects all of whom reported contact with an open flame. The presence of singed hair on the back of the hand can be of great evidential value, though the corresponding distribution pattern must be carefully interpreted.     

The spatial distribution of zinc and cobalt in single human head hairs.

The concentration patterns of indigenous zinc and of zinc and cobalt absorbed from radiotracer solutions have been measured via flameless AA and radioactivity assay, respectively, in individual human head hairs. Patterns for indigenous zinc were found to be relatively flat and featureless. Patterns for absorbed zinc (like those for indigenous and absorbed copper in the same subjects) showed increasing concentrations with increasing distance from the root, plus zones of locally increased concentrations at positions different from those for zones of increased copper concentrations. In bleached hair, indigenous zinc concentrations were decreased, and absorbed zinc and cobalt concentrations were increased compared to values in normal hair. The data for absorbed zinc and cobalt were interpreted in terms of a variable concentration of metal-binding sites in the hair structure, coupled with an increased porosity induced by hair bleaching. The flat patterns for the indigenous zinc content were interpreted as indicating the importance of dietary zinc and incorporation via the follicle, and the unimportance of external contamination as the source of this zinc. The forensic implications of the data have been discussed.     

Statistical evaluation of the evidential value of human hairs possibly coming from multiple sources

A concept of the mathematical evaluation of human hair evidence is derived. This concept can be realized in a special computer program, the output of which is an incrimination probability. The problems of not knowing the true number of sources and the correct partition of hairs corresponding to their sources are solved from the point of view of avoiding an unjustified incrimination.     

Sex determination from plucked human hairs without epithelial root sheath. II. Depigmentation of melanin in the hair cortex before Feulgen reaction

In hair roots devoid of the epithelial root sheath, an attempt was made to decolorize the melanin granules without affecting the Feulgen reaction for the sex chromatin. The hair samples were treated with 0.25% potassium permanganate for 1 hour, 0.3% hydrogen peroxide for 1 minute and 5% oxalic acid for 5 minutes, and then stained with Feulgen. The frequency of sex chromatins ranged from 22% to 47% (average 32%) in female samples and from 0% to 8% (average 5%) in male samples. Thus, the frequency distributions of the male and female samples were completely independent of each other. The sex chromatins in dried female hairs were detectable at a frequency of 16 – 26% several weeks after plucking. The depigmentation procedure almost completely bleached the melanin granules in the hair cortex, and produced no harmful effect on the Feulgen reaction that followed.     

Morphological structure of the domestic cat (Felis catus) hair

Felis catus hairs from different parts of its body were examined. Examination of some hair parameters allow the author to propose the following strategy of cat identification: 1) hair length divides cats into long- and short-haired; 2) identification of the species: a) long-haired--by medullary substance/hair thickness ratio; b) short-haired--by the presence or absence of osteal and transition hairs, by thickness of the osteal hairs. This scheme allows identification of the species of an individual cat.     

Results of a collaborative study of the EDNAP group regarding mitochondrial DNA heteroplasmy and segregation in hair shafts

A collaborative exercise was carried out by the European DNA Profiling Group (EDNAP) in order to evaluate the distribution of mitochondrial DNA (mtDNA) heteroplasmy amongst the hairs of an individual who displays point heteroplasmy in blood and buccal cells. A second aim of the exercise was to study reproducibility of mtDNA sequencing of hairs between laboratories using differing chemistries, further to the first mtDNA reproducibility study carried out by the EDNAP group. Laboratories were asked to type 2 sections from each of 10 hairs, such that each hair was typed by at least two laboratories. Ten laboratories participated in the study, and a total of 55 hairs were typed. The results showed that the C/T point heteroplasmy observed in blood and buccal cells at position 16234 segregated differentially between hairs, such that some hairs showed only C, others only T and the remainder, C/T heteroplasmy at varying ratios. Additionally, differential segregation of heteroplasmic variants was confirmed in independent extracts at positions 16093 and the poly(C) tract at 302-309, whilst a complete A-G transition was confirmed at position 16129 in one hair. Heteroplasmy was observed at position 16195 on both strands of a single extract from one hair segment, but was not observed in the extracts from any other segment of the same hair. Similarly, heteroplasmy at position 16304 was observed on both strands of a single extract from one hair. Additional variants at positions 73, 249 and the HVII poly(C) region were reported by one laboratory; as these were not confirmed in independent extracts, the possibility of contamination cannot be excluded. Additionally, the electrophoresis and detection equipment used by this laboratory was different to those of the other laboratories, and the discrepancies at position 249 and the HVII poly(C) region appear to be due to reading errors that may be associated with this technology. The results, and their implications for forensic mtDNA typing, are discussed in the light of the biology of hair formation.     

同一个体发毛角蛋白电泳谱型的分析

用SDS -PAGGE对收集到的 2 0例人体表毛发 (头发、阴毛、腋毛、腿毛 )角蛋白组分进行了分析。结果表明 ,同一个体毛发角蛋白电泳谱型基本相同 ,用激光光密度仪对电泳凝胶板扫描后证实 ,同一个体毛发角蛋白组分相对百分含量也无明显差异 ;人头部不同部位 (顶部、左侧、右侧、额部、枕部 )头发角蛋白的电泳谱型和角蛋白组分相对百分含量也基本相同。同一个体毛发角蛋白组分的分析 ,可为法医物证学鉴定中的毛发个人识别提供重要的依据。