Ninety-five percent probability of paternity with HLA,ABO and haptoglobins

Using HLA tissue typing as the basic genetic test along with ABO and haptoglobin typing, it is generally possible either to exclude a putative father conclusively or, in non-exclusion cases, to assign a greater than 95% probability of paternity. In 22 of 53 non-exclusion cases, the putative father had a probability of paternity above 99% based on these genetic tests.     

Calculating the exclusion probability and paternity index for X-chromosomal loci in the presence of substructure

There has been recent interest in the use of X-chromosomal loci for forensic and relatedness testing casework, with many authors developing new X-linked short tandem repeat (STR) loci suitable for forensic use. Here we present formulae for two key quantities in paternity testing, the average probability of exclusion and the paternity index, which are suitable for X-chromosomal loci in the presence of population substructure.     

Correlation of paternity index with probability of exclusion and efficiency criteria of genetic markers for parternity testing

The statistical correlation between the chance of paternity exclusion and paternity index is explored to derive a new criterion of judging the efficiency of an array of genetic determinations for parentage diagnosis. The theoretical basis is illustrated with allele frequency data on genetic markers used in a paternity testing protocol to examine the possible effects of changing the genetic systems on the prospect of identifying fathers by genetic markers.     

A search for obligatory paternal alleles in a DNA database to find an alleged rapist in a fatherless paternity case

Abstract: A sexual assault case resulted in a pregnancy, which was subsequently aborted. The alleged father of the fetus was unknown. Maternal and fetal types were obtained using the 11‐locus AmpF?STR^® SGM Plus^® kit. The national DNA database was searched for the paternal obligatory alleles and detected two suspects who could not be excluded as father of the male fetus. Additional typing using the AmpF?STR^® Minifiler^? kit, containing three additional autosomal loci, was not sufficient to exclude either suspect. Subsequent typing using the PowerPlex^® 16, containing four additional loci, and Y‐Filer^? kits resulted in excluding one suspect. Searching a database for paternal obligatory alleles can be fruitful, but is fraught with possible false positive results so that finding a match must be taken as only preliminary evidence.     

Estimating the probability of allelic drop-out of STR alleles in forensic genetics

In crime cases with available DNA evidence, the amount of DNA is often sparse due to the setting of the crime. In such cases, allelic drop-out of one or more true alleles in STR typing is possible. We present a statistical model for estimating the per locus and overall probability of allelic drop-out using the results of all STR loci in the case sample as reference. The methodology of logistic regression is appropriate for this analysis, and we demonstrate how to incorporate this in a forensic genetic framework.     

亲子鉴定中STR位点数选择及其应用价值研究

目的对在亲子鉴定中STR位点数的选择及其鉴定应用价值进行研究。方法将CODIS13个STR位点分为四个观测组,观测对象包括排除亲权的母亲-孩子-假设父亲三人组合102例,以及肯定亲权的母亲-孩子-假设父亲三人组合100例,通过310遗传分析仪对荧光复合扩增产物进行分型检测。结果各STR观察组出现的最低排除指标数与各观察组累积非父排除概率(CPE)值成一定正相关性,CPE值超过99.99%的两个STR观察组其出现的最低排除指标数为三个,同时这两个STR观察组在肯定亲权的案例分析中,其亲子关系概率值(RCP)值都超过了99.99%。结论对于亲子鉴定中的STR位点检测系统,其非父排除指标应为三个以上,其累积非父排除概率(CPE)值达到99.99%时,就可以认为该STR位点检测系统具有了相关的鉴定应用价值。     

A simple spectrophotometric method for the determination of carboxyhemoglobin in blood

The spectrophotometric method for the determination of carboxyhemoglobin (HbCO) in blood reported by Fretwurst and Meinecke was modified so as to give the same values of percentage HbCO (HbCO%) as those determined by the oxygen electrode method. Values of HbCO% of nine practical samples determined by both the oxygen electrode method and the present method were nearly identical regardless of the presence of methemoglobin (Met-Hb) in blood. The present method is suitable for forensic practice.     

A simple magneto-optical method for the restoration of erased markings in metals

There are different techniques for the restoration of erased markings in metals. Non-destructive methods are generally preferable. The only frequently used non-destructive method is the magnetic technique. The different kinds of magnetic restoration methods are discussed in the article. In the experiments described, the applicability of magneto-optical methods for the restoration of obliterated markings was examined. The results show that the methods are suitable and the required equipment does not cause high expenses.     

Computation of likelihood ratios in fingerprint identification for configurations of any number of minutiae

Recent court challenges have highlighted the need for statistical research on fingerprint identification. This paper proposes a model for computing likelihood ratios (LRs) to assess the evidential value of comparisons with any number of minutiae. The model considers minutiae type, direction and relative spatial relationships. It expands on previous work on three minutiae by adopting a spatial modeling using radial triangulation and a probabilistic distortion model for assessing the numerator of the LR. The model has been tested on a sample of 686 ulnar loops and 204 arches. Features vectors used for statistical analysis have been obtained following a preprocessing step based on Gabor filtering and image processing to extract minutiae data. The metric used to assess similarity between two feature vectors is based on an Euclidean distance measure. Tippett plots and rates of misleading evidence have been used as performance indicators of the model. The model has shown encouraging behavior with low rates of misleading evidence and a LR power of the model increasing significantly with the number of minutiae. The LRs that it provides are highly indicative of identity of source on a significant proportion of cases, even when considering configurations with few minutiae. In contrast with previous research, the model, in addition to minutia type and direction, incorporates spatial relationships of minutiae without introducing probabilistic independence assumptions. The model also accounts for finger distortion.     

A simple method for postmortem detection of acute myocardial infarction

The analysis of K/Na ion ratio of myocardium was used for the postmortal determination of the early myocardial infarction. The ion content of heart tissue was measured with flame spectrometer after the decomposition of myocardium by Lumatom tissue solubizer. The ion contents and their ratios correlate well with the electrocardiogram, the clinical data, the autopsy and histological findings. In some cases the change of the K/Na ion ratio was the only alteration that suggested an early stage of myocardial infarction. The Lumatom tissue solubizer can be very useful in determination of trace elements from any organic samples.     

A simple method for preparing human sketetal material for forensic examination

A method using dilute sodium hypochlorite for the cleaning of human skeletal material from decomposed bodies is described. With this simple procedure, which requires minimal expenditure of time and money, bones may be cleaned in a manner that produces specimens satisfactory for forensic examination, documentation of injuries, and jury presentation.     

共有基因数在同胞鉴定中应用的研究

目的　探索利用两个体间共有基因数目资料进行同胞关系鉴定的应用价值。方法　根据 80 7对同胞及无关个体的 13个STR基因座的分型结果 ,进行统计学计算。结果　同胞间及无关个体间共有基因数目均符合正态分布 ,分别得到同胞及无关个体关系的判别函数和后验概率 ,以及该方法的平均错判率。其中同胞组判别函数为 :L同胞 =-2 7 0 870 3 +3 2 0 2 3 2S (S为共有基因个数 ) ;无关个体组判别函数为 :L无关 =-7 495 63 +1 685 0 9S ,用上述判别函数进行同胞 /无关个体关系判别时的平均错判率为 0 0 2 65。结论　当共有基因数目大于 17或小于 8时 ,两个体为同胞或无关个体的后验概率分别大于 0 9980和 0 9994。此方法不失为同胞关系鉴定的可信度较高的方法。     

A method for calculating the strength of evidence associated with an earwitness's claimed recognition of a familiar speaker

The present paper proposes and demonstrates a method for assessing strength of evidence when an earwitness claims to recognize the voice of a speaker who is familiar to them. The method calculates a Bayes factor that answers the question: What is the probability that the earwitness would claim to recognize the offender as the suspect if the offender was the suspect versus what is the probability that the earwitness would claim to recognize the offender as the suspect if the offender was not the suspect but some other speaker from the relevant population? By “claim” we mean a claim made by a cooperative earwitness not a claim made by an earwitness who is intentionally deceptive. Relevant data are derived from naïve listeners' responses to recordings of familiar speakers presented in a speaker lineup. The method is demonstrated under recording conditions that broadly reflect those of a real case.