Quantitative behavioral genetic and molecular genetic foundations of the approach and avoidance strategies.

Two studies examined genetic and environmental influences on traits proposed by the revised Reinforcement Sensitivity Theory (rRST) of personality. Both quantitative and molecular behavioral genetic methods were applied considering the effects of COMT, DRD2, HTR1A and TPH2 single nucleotide polymorphisms (SNPs). Study one included 274 monozygotic and 154 dizygotic twins for the quantitative behavioral study; and in study two there were 431 twins for the molecular genetic study. The Reinforcement Sensitivity Questionnaire was used to assess basic personality traits defined by the rRST. Univariate biometric modeling suggested that genetic influences accounted for 34-44% of variance of Behavioral Approach System (BAS), Behavioral Inhibition System (BIS) and Fight-Fligh-Freeze System. Molecular genetic analyses proposed the significant main effect of COMT SNP on the BAS and TPH2 SNP on the BIS, and pointed out epistatic effects of COMT x DRD2 on BAS and HTR1A x TPH2 on Fight. Results demonstrated substantial heritability for all rRST constructs, as well as for differences in the molecular genetic basis of both approach-related and avoidance-related dimensions.

Twin study of laboratory-induced aggression.

The aim of this study was to explore genetic and environmental contributions to laboratory-induced aggressive behavior. On a sample of 478 adult twins (316 monozygotic), the Competitive Reaction Time Task was used for aggression induction. The results showed that the initial, basic level of aggression could be explained by both shared (45%) and nonshared environmental factors (55%), while only nonshared environmental factors (100%) had a significant influence on changes in aggression as provocation increased. Genetic factors had no influence on laboratory-induced aggression. The results highlight the importance of environmental factors in shaping situation-specific aggressive responses to provocation.

First all-in-one diagnostic tool for DNA intelligence: genome-wide inference of biogeographic ancestry, appearance, relatedness, and sex with the Identitas v1 Forensic Chip.

When a forensic DNA sample cannot be associated directly with a previously genotyped reference sample by standard short tandem repeat profiling, the investigation required for identifying perpetrators, victims, or missing persons can be both costly and time consuming. Here, we describe the outcome of a collaborative study using the Identitas Version 1 (v1) Forensic Chip, the first commercially available all-in-one tool dedicated to the concept of developing intelligence leads based on DNA. The chip allows parallel interrogation of 201,173 genome-wide autosomal, X-chromosomal, Y-chromosomal, and mitochondrial single nucleotide polymorphisms for inference of biogeographic ancestry, appearance, relatedness, and sex. The first assessment of the chip's performance was carried out on 3,196 blinded DNA samples of varying quantities and qualities, covering a wide range of biogeographic origin and eye/hair coloration as well as variation in relatedness and sex. Overall, 95 % of the samples (N = 3,034) passed quality checks with an overall genotype call rate >90 % on variable numbers of available recorded trait information. Predictions of sex, direct match, and first to third degree relatedness were highly accurate. Chip-based predictions of biparental continental ancestry were on average ~94 % correct (further support provided by separately inferred patrilineal and matrilineal ancestry). Predictions of eye color were 85 % correct for brown and 70 % correct for blue eyes, and predictions of hair color were 72 % for brown, 63 % for blond, 58 % for black, and 48 % for red hair. From the 5 % of samples (N = 162) with <90 % call rate, 56 % yielded correct continental ancestry predictions while 7 % yielded sufficient genotypes to allow hair and eye color prediction. Our results demonstrate that the Identitas v1 Forensic Chip holds great promise for a wide range of applications including criminal investigations, missing person investigations, and for national security purposes.

Improved eye- and skin-color prediction based on 8 SNPs.

AIM: To improve the 7-plex system to predict eye and skin color by increasing precision and detailed phenotypic descriptions. METHODS: Analysis of an eighth single nucleotide polymorphism (SNP), rs12896399 (SLC24A4), showed a statistically significant association with human eye color (P=0.007) but a rather poor strength of agreement (κ=0.063). This SNP was added to the 7-plex system (rs12913832 at HERC2, rs1545397 at OCA2, rs16891982 at SLC45A2, rs1426654 at SLC24A5, rs885479 at MC1R, rs6119471 at ASIP, and rs12203592 at IRF4). Further, the instruction guidelines on the interpretation of genotypes were changed to create a new 8-plex system. This was based on the analysis of an 803-sample training set of various populations. The newly developed 8-plex system can predict the eye colors brown, green, and blue, and skin colors light, not dark, and not light. It is superior to the 7-plex system with its additional ability to predict blue eye and light skin color. RESULTS: The 8-plex system was tested on an additional 212 samples, the test set. Analysis showed that the number of positive descriptions for eye colors as being brown, green, or blue increased significantly (P=6.98e-15, z-score: -7.786). The error rate for eye-color prediction was low, at approximately 5%, while the skin color prediction showed no error in the test set (1% in training set). CONCLUSIONS: We can conclude that the new 8-plex system for the prediction of eye and skin color substantially enhances its former version.

Latent, genetic, and molecular genetic structure of the Wisconsin Card Sorting Test.

OBJECTIVE: The main goal of this study was to explore the latent structure and genetic basis of cognitive processes involved in the Wisconsin Card Sorting Task (WCST) within phenotypic, behavioral genetic, and molecular genetic research paradigms. METHOD: The sample used in phenotypic and behavioral genetic analyses comprised 468 twins (154 monozygotic and 80 dizygotic twin pairs), while molecular genetic analyses were performed on 404 twins from the same sample. The zygosity of most twin pairs (96.8%) was determined via deoxyribonucleic acid (DNA) analysis of buccal swabs. Trained researchers administered the Wisconsin Card Sorting Test (WCST; Heaton et al., 1993) to the entire sample. RESULTS: A phenotypic factor analysis of WCST variables suggested a single-factor solution. Overall heritability ranged from 0.19 to 0.23 across different measures of the WCST. The presence of a single general genetic factor, which could be identified from different measures of the WCST, indicated the unity of various WCST indicators and the existence of a common basic ability. Performance on the WCST did not reveal significant differences between the three genotypes on catechol-O-methyltransferase (COMT) and dopamine receptor D2 (DRD2). Carriers of the brain-derived neurotrophic factor (BDNF) Met + genotype exhibited better performance in cognitive functions in comparison to the BDNF Met- genotype. CONCLUSIONS: This study highlighted similarities in the phenotypic and genetic structures of the WCST, suggesting one general factor underlying different cognitive functions. The BDNF Met + genotype showed significant main effects on different WCST measures. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Differences in MB-COMT DNA methylation in monozygotic twins on phenotypic indicators of impulsivity.

Epigenetic modifications of the membrane bound catechol-O-methyltransferase (MB-COMT) gene may affect the enzymatic degradation of dopamine, and consequently, human behavior. This study investigated the association between membrane bound catechol-O-methyltransferase DNA methylation (DNAm) differences in 92 monozygotic (MZ) twins with phenotypic manifestations of cognitive, behavioral, and personality indicators associated with reward-related behaviors and lack of control. We used pyrosequencing to determine DNAm of the regulatory region of membrane bound catechol-O-methyltransferase in saliva DNA. Results of intrapair differences in the percentage of membrane bound catechol-O-methyltransferase DNAm at each of five CpG sites show that there are associations between phenotypic indicators of lack of control and membrane bound catechol-O-methyltransferase DNAm differences on CpG1, CpG2 and CpG4, suggesting the common epigenetic patterns for personality traits, cognitive functions, and risk behaviors.

Malignant tumors and forensics--dilemmas and proposals.

AIM: To evaluate the effect of genetic instability and degradation in archived histology samples from cancerous tumors and to investigate the validity of short tandem repeat (STR) typing of these samples and its potential effect on human identification. METHODS: Two hundred and twenty eight slides of archival pathology tissues from 13 different types of malignant tumors were compared with healthy tissues from the same individuals. DNA analysis was performed using standard techniques for forensic STR analysis, PowerPlex16 and Identifiler on 2 distinct sample sets. Genetic instability was assessed by comparing reference tissues with cancerous tissues derived from the same individual. Loss of heterozygosity, a > or =50% reduction in heterozygosity ratio between healthy and diseased samples, and microsatellite instability, the presence of an additional allele not present in reference tissue, were assessed. The quality of profiles obtained with respect to completeness among the archived samples and degradation using the 2 platforms were also compared. RESULTS: Profiles obtained using the Identifiler system were generally more complete, but showed 3-fold higher levels of instability (86%) than those obtained using PowerPlex 16 (27%). Instances of genetic instability were distributed throughout all loci in both multiplex STR systems. CONCLUSION: After having compared 2 widely used forensic chemistries, we suggest individual validation of each kit for use with samples likely to exhibit instability combined with fixation induced degradation or artifact. A "one size fits all" approach for interpretation of these samples among commercially available multiplexes is not recommended.

The characteristics of head wounds inflicted by "humane killer" (captive-bolt gun)--a 15-year study.

The "humane killer" or captive-bolt gun, is the tool/weapon widely used in meat industry and private farmer households for slaughtering animal stock. Out of 17,250 autopsies performed at the Institute of Forensic Medicine in Novi Sad during the 15-year period (1991-2005), 29 cases of suicides and two homicides were committed by captive-bolt pistols. Wounds inflicted by captive-bolt guns have specific morphological features, distinctive from wounds made by other kinds of hand firearms. Selected features of the captive-bolt wounds (punched round entrance and a double pattern of smoke soiling) depend on distance and angle of instrument at the time of firing. Autopsy findings were compared with an experimental model consisting of 20 domestic pigs. Obtained results confirmed that the appearance of the entrance hole and soot deposits, along with differences in shape, location, extent, and density of soot blackening, could be useful in identification of weapon, direction of discharge, shooting distance, and angle of the muzzle to the frontal and sagittal planes of the head at the moment of fire.

Multiplex short tandem repeat DNA analysis confirms the accuracy of p57(KIP2) immunostaining in the diagnosis of complete hydatidiform mole.

Detailed histopathologic examination remains to be the basis for the diagnosis of hydatidiform mole (HM). However, poor sampling, necrosis, and earlier uterine evacuation can lead to uncertainty in the diagnosis. Also, the criteria are subjective, resulting in considerable interobserver variability. The p57(KIP2) gene is paternally imprinted and maternally expressed, and the presence of its protein product serves as a surrogate marker for the nuclear maternal genome. Because a complete HM (CHM) is the only type of conceptus lacking a maternal contribution, p57(KIP2) immunostaining is correspondingly absent, whereas it is present in CHM mimics. Although analysis of DNA microsatellite polymorphisms is a reliable method for the diagnosis and classification of HM, it is not universally available. To assess the relative accuracy of p57(KIP2) immunostaining and molecular diagnosis by nuclear DNA microsatellite polymorphisms in discriminating CHM from its mimics, we analyzed archival tissue from 33 case patients (7 with a definitive diagnosis of CHM, 16 with a possible diagnosis of HM, and 10 with normal placentas) by both methods. Concordant results were obtained in all cases, and p57(KIP2) immunostaining accurately identified all cases of CHM from the groups with a definitive or possible diagnosis of HM. p57(KIP2) immunohistochemistry is a time- and cost-effective means of distinguishing CHM from its mimics in challenging cases.

Uveal melanocytomas: genetic comparison with uveal and dermal melanomas.

OBJECTIVE: Melanocytomas of the eye are typically benign tumors that may be associated with nevi and melanomas. In this study, we assessed the genetic data of melanocytomas and compared them with nevi and melanomas of both the eyes and the skin. DESIGN: We microdissected 8 melanocytomas, 13 uveal melanomas, and 10 cutaneous melanomas and analyzed loss of heterozygosity markers on chromosome bands 1p36, 6q22-23.3, 9p21, and 10q23, which represent genetic loci associated with advanced dermal melanocytic lesions. RESULTS: There was no loss of heterozygosity in any of the melanocytomas. However, many loss of heterozygosity events were found in uveal and cutaneous melanomas, most frequently involving chromosome 1 damage followed by chromosome 9 and 10 alterations. CONCLUSION: Based on the absence of loss of heterozygosity in melanocytomas, specifically the locus that is lost most often in dysplastic nevi of the skin, we conclude that melanocytomas represent an entity that is different from melanomas or may be similar to that of dermal benign nevi. CLINICAL RELEVANCE: Our results confirm that melanocytomas represent nonagressive lesions that do not demand radical surgery.

Assay Development and Validation of an 8-SNP Multiplex Test to Predict Eye and Skin Coloration.

Identifying human remains is one of the many responsibilities of forensic scientists. An eye- and skin-color predictor translates genotypic information into phenotypic description. Eight single nucleotide polymorphisms (SNPs) are utilized for this predictor, five for eye, and six for skin coloration. Here, we describe the development and validation of an 8-SNP multiplex assay that consists of a multiplex PCR, followed by a multiplexed single-base primer extension reaction generating fluorescently labeled oligonucleotides of distinct length that are detected by multicolor capillary electrophoresis. Validation of this assay included tests for reproducibility, reliability, sensitivity, species specificity, its performance on degraded DNA, and on forensic samples. It can be concluded that the 8-SNP multiplex assay is robust and can be used on challenging samples, including bones, to reliably determine the genotypes to predict eye and skin color of individuals. This information can assist in the identification of human remains and missing persons.

Multiplex DNA short tandem repeat analysis. A useful method for determining the provenance of minute fragments of formalin-fixed, paraffin-embedded tissue.

A tiny fragment of high-grade carcinoma was found in histologic sections and in the paraffin block of a benign cervical polyp from a patient with no clinical evidence of malignancy. Thus, it raised the suspicion of block contamination. No malignant tumor was processed the same day as the polyp; however, a similar tumor had been processed 6 days earlier. Multiplex DNA short tandem repeat analysis was applied to paraffin-extracted tissue samples obtained from the polyp, the suspected contaminant, the patient's additional cervical biopsy specimen, and the putative source of contamination. The results demonstrated that the suspected contaminant and the patient's cervical tissue could not have come from the same patient and that the suspected contaminant derived from the tumor processed earlier, without reasonable doubt. We hypothesize that this friable tumor escaped from cassettes into the processor and contaminated the polyp specimen. Multiplex DNA short tandem repeat analysis can be applied to determine the provenance of minute tissue samples in surgical pathology.

Interpretation guidelines for multilocus STR forensic profiles from low template DNA samples.

Low template (LT) DNA testing is a more sensitive method of PCR DNA typing which tests lower quantities of DNA compared to traditional PCR DNA protocols. Methods applied in this testing involve amplification or postamplification efforts to increase detection sensitivity. Establishing the interpretation rules of the results obtained is condition sine qua non for successful incorporation of this valuable technique into forensic casework. Here we describe a successfully optimized and validated approach to interpretation of LT-DNA samples.

Verification of eye and skin color predictors in various populations.

Validation of testing methods is an essential feature in all scientific endeavors, but it is particularly important in forensics. Due to the sensitive nature of these investigations and the limited sample size it is crucial to validate all employed procedures. This includes novel forensic phenotypic DNA tests, to learn more of their capabilities and limitations before incorporating them as routine methods. Ideally, validations are performed on large sample sets that mimic real cases. Recently, three phenotypic predictors, two for eye colors and one for skin color have been published (Spichenok et al., 2011; Walsh et al., 2011). These predictors are well-defined by a selection of single nucleotide polymorphisms (SNPs) and unambiguous instructions on how to interpret the genotypes. These standardized approaches have the advantages that they can be applied in diverse laboratories leading to the same outcome and offer the opportunity for validation. For these tests to be used on the characterization of human remains, they should be validated on various populations to perform reliably without prior knowledge of ethnic origin. Here, in this study, these eye and skin color predictors were validated on new sample sets and it could be confirmed that they can be applied in various populations, including African-American, South Asian (dark), East Asian (light), European, and mixed populations. The outputs were either predictive or inconclusive. Predictions were then compared against the actual eye and skin colors of the tested individuals. The error-rates varied; they were low for the predictors that describe the eye and skin color exclusively (non-brown or non-blue and non-white or non-dark, respectively) and higher for the predictor that describes individual eye colors (blue, brown, and intermediate/green), because of uncertainties with the green eye color prediction. Our investigation deepens the insight for these predictors and adds new information.

Validation of a DNA mixture statistics tool incorporating allelic drop-out and drop-in.

DNA mixture analysis is a current topic of discussion in the forensics literature. Of particular interest is how to approach mixtures where allelic drop-out and/or drop-in may have occurred. The Office of Chief Medical Examiner (OCME) of The City of New York has developed and validated the Forensic Statistical Tool (FST), a software tool for likelihood ratio analysis of forensic DNA samples, allowing for allelic drop-out and drop-in. FST can be used for single source samples and for mixtures of DNA from two or three contributors, with or without known contributors. Drop-out and drop-in probabilities were estimated empirically through analysis of over 2000 amplifications of more than 700 mixtures and single source samples. Drop-out rates used by FST are a function of the Identifiler(®) locus, the quantity of template DNA amplified, the number of amplification cycles, the number of contributors to the sample, and the approximate mixture ratio (either unequal or approximately equal). Drop-out rates were estimated separately for heterozygous and homozygous genotypes. Drop-in rates used by FST are a function of number of amplification cycles only. FST was validated using 454 mock evidence samples generated from DNA mixtures and from items handled by one to four persons. For each sample, likelihood ratios (LRs) were computed for each true contributor and for each profile in a database of over 1200 non-contributors. A wide range of LRs for true contributors was obtained, as true contributors' alleles may be labeled at some or all of the tested loci. However, the LRs were consistent with OCME's qualitative assessments of the results. The second set of data was used to evaluate FST LR results when the test sample in the prosecution hypothesis of the LR is not a contributor to the mixture. With this validation, we demonstrate that LRs generated using FST are consistent with, but more informative than, OCME's qualitative sample assessments and that LRs for non-contributors are appropriately assigned.

Prediction of eye and skin color in diverse populations using seven SNPs.

An essential component in identifying human remains is the documentation of the decedent's visible characteristics, such as eye, hair and skin color. However, if a decedent is decomposed or only skeletal remains are found, this critical, visibly identifying information is lost. It would be beneficial to use genetic information to reveal these visible characteristics. In this study, seven single nucleotide polymorphisms (SNPs), located in and nearby genes known for their important role in pigmentation, were validated on 554 samples, donated from non-related individuals of various populations. Six SNPs were used in predicting the eye color of an individual, and all seven were used to describe the skin coloration. The outcome revealed that these markers can be applied to all populations with very low error rates. However, the call-rate to determine the skin coloration varied between populations, demonstrating its complexity. Overall, these results prove the importance of these seven SNPs for potential forensic tests.

Forensic applications of laser capture microdissection: use in DNA-based parentage testing and platform validation.

AIM: To report on the successful use of Laser Capture Microdissection (LCM) as a tool for isolation of human chorionic villi from admixed maternal tissue. Subsequent DNA isolation for forensic short tandem repeat (STR) analysis for parentage testing was performed in two cases of alleged sexual assault of female victims. We also performed validation of the LCM instrument platform, using archival formalin-fixed human fetal products of conception (POC), for which microdissection was utilized to separate maternal (decidua) and fetal (chorionic villus) components. METHODS: To isolate DNA from placental chorionic villi admixed with maternal decidua recovered after spontaneous or therapeutic abortion, LCM was used to separate fetal from maternal cells. In contrast to the relatively crude conventional microdissection performed using a narrow pipette, needle, or scalpel blade, LCM allows cell- or tissue-specific isolation of placental chorionic villi from archival paraffin-embedded tissue sections, leaving the maternal tissue intact. RESULTS: After polymerase chain reaction (PCR) amplification of villi after LCM of 9-15 STR loci, the quantity and quality of DNA yielded from fetal cells isolated by LCM was sufficient for PCR analysis and successful forensic parentage testing. The validation data obtained on two sets of formalin-fixed archival POC tissues from anonymous donors demonstrated the encouraging reproducibility of these protocols and procedures. CONCLUSION: We demonstrated the reliability and utility of LCM for forensic applications when high specificity of a particular analyzed cell population or tissue is required. Care must be taken during routine pathology procedures to avoid contamination of tissues with admixture of extraneous DNA.

World Trade Center human identification project: experiences with individual body identification cases.

AIM: To present individual body identification efforts, as part of the World Trade Center (WTC) mass disaster identification project. METHODS: More than 500 samples were tested by using polymerase chain reaction (PCR) amplification and short tandem repeat (STR) typing. The extent to which the remains were fragmented and affected by taphonomic factors complicated the identification project. Anthropologists reviewed 19,000 samples, and detected inconsistencies in 69, which were further split into 239 new cases and re-sampled by DNA specialists. RESULTS: The severity and nature of the disaster required an interdisciplinary effort. DNA profiling of 500 samples was successful in 75% of the cases. All discrepancies, which occurred between bone and tissue samples taken from the same body part, were resolved by re-sampling and re-testing of preferably bone tissue. Anthropologists detected inconsistencies in 69 cases, which were then split into 239 new cases. Out of 125 "split" cases, 65 were excluded from their original case. Of these 65 cases, 37 did not match any profiles in M-FISys, probably because profiles were incomplete or no exemplar for the victim was available. Out of the 60 remains not excluded from their original case, 30 were partial profiles and did not reach the statistical requirement to match their original case, because the population frequency of the DNA profile had to be