Forensic Biology: Serology and DNA

Abstract

AbstractCrime Laboratories routinely process evidence from criminal cases for the presence of biological fluids such as blood, semen, and saliva in order to obtain DNA profiles. Forensic Biology encompasses both Forensic Serology and DNA testing. Prior to examination, it is important for the forensic scientist to evaluate the type of crime and the samples submitted so that the evidence can be processed in the proper order for the type of testing needed. Typically, evidence will be analyzed using a mix of presumptive and confirmatory tests to determine the presence of biological stains prior to DNA analysis, although this may not always be feasible when the amount of sample is limited. These Forensic Serology tests assist the analyst in determining which samples will go forward to DNA testing. Forensic DNA testing in most crime laboratories in the United States is done using short tandem repeat (STR) analysis of the 13 core CODIS STR loci. This chapter introduces routine serology procedures, the DNA testing process, the interpretation of DNA profiles, and the national DNA database, CODIS.KeywordsAcid phosphatasealternate light source (ALS)bloodchain of custodyCODISdeoxyribonucleic acid (DNA)differential extractionevidenceforensic serologyLaboratory Information Management System (LIMS)low copy number (LCN)mitochondrial DNA (mtDNA)presumptive testprostate-specific antigen (PSA)semenshort tandem repeat (STR)single-nucleotide polymorphism (SNP)spermatozoaY-STR