ABSTRACT
Amplification behavior of one chromosome locus (D17S5), widely used in identification studies, is investigated. The effect of preferable amplification of alleles, characteristic of this locus, often leads to an erroneous conclusion about homozygosity. Our studies showed, that along with the hazard of typing false homozygotes in analysis of locus D17S5, more intricate cases with genotype distortion can occur in expert practice, which may be characterized not only by partial loss of the true alleles, but even by amplification of nonspecific (nonallele) fragments simulating the false-heterozygotic allele profile. Analysis of the stability of amplification profile helps solve this problem.
Subject(s)
Alleles , Chromosomes, Human/genetics , Gene Amplification/genetics , Nucleic Acid Amplification Techniques , DNA/isolation & purification , Electrophoresis, Agar Gel , Forensic Medicine , Genotype , Homozygote , Humans , Polymerase Chain Reaction , Regression AnalysisABSTRACT
The authors discuss the problem of selective derivation of the genetic material of spermatozoa for molecular genetic identification from mixed biological traces containing sperm on material evidence. Possible methods of improving the efficacy of differential lysis of cells present in mixed traces are analyzed. Effects of some routinely used extractants on biological substrata, most often contaminating the sperm in expert material, have been studied, and conditions for their most complete elimination from objects of investigation optimized.
Subject(s)
Expert Testimony/methods , Forensic Medicine/methods , Polymerase Chain Reaction/methods , Cell Fractionation/methods , DNA/analysis , DNA/isolation & purification , Electrophoresis, Agar Gel , Expert Testimony/standards , Forensic Medicine/standards , Forensic Medicine/statistics & numerical data , Humans , Male , Polymerase Chain Reaction/standards , Polymerase Chain Reaction/statistics & numerical data , Regression Analysis , Russia , Spermatozoa/chemistry , Spermatozoa/ultrastructureABSTRACT
Analyses the effects of nonoptimal conditions of polymerase chain reaction concerning the initial amount of matrix DNA and duration of its amplification on the amplification picture of hypervariable tandem-arranged locuses of human genome. Shows the causes of its possible ambiguous interpretation leading to inadequate expert conclusions in forensic gene-identification expert evaluation. Outlines the approaches to solution of this problem.
Subject(s)
Forensic Medicine/methods , Polymerase Chain Reaction/methods , Polymorphism, Restriction Fragment Length , DNA/blood , Electrophoresis, Agar Gel , Humans , Lymphocytes/chemistryABSTRACT
A new approach to the identification of a father at the early stages of embryonal development has been developed, validated, and successfully tried. This approach, based on molecular genetic analysis of multiallele loci of human genome using polymerase chain reaction is completely justified and advisable for the relevant expert evaluations.
Subject(s)
Embryonic and Fetal Development/genetics , Forensic Medicine/methods , Paternity , Abortion, Induced , Alleles , DNA/blood , DNA/genetics , DNA/isolation & purification , Electrophoresis, Agar Gel , Female , Fetal Blood/chemistry , Gestational Age , Humans , Immunoblotting , Male , Nucleic Acid Hybridization , Polymerase Chain Reaction/methods , Pregnancy , RapeABSTRACT
In this article phenomena related to sex heteromorphism of restrictase hydrolysates of DNA, isolated from objects of expert analysis was recommended for use. The performed investigations allow one to work out the system of discriminating sex of biological objects, based on restrictase analysis of human DNA and on registration of sex-specific restrictase fragments. Possibilities of method and its value for gene-identification expertise were illustrated using certain cases from expert practice.
Subject(s)
DNA/analysis , Forensic Medicine/methods , Restriction Mapping , Sex Determination Analysis , Autoradiography , Electrophoresis, Agar Gel , Female , Humans , Male , Nucleic Acid HybridizationABSTRACT
Use of DNA "fingerprinting" method for biological analysis of material evidences exhibit new potentials for making concrete expert conclusions. But such expertise is time consuming and difficult to perform that's why it is important to evaluate fitness of expert material for DNA fingerprinting at early stages of object investigation. Method of preliminary treatment of objects sent for DNA fingerprint expertise in case of sexual assault is suggested and tested. This method allows one to evaluate objects easily from the standpoint of possibility to perform such investigation.
