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MATH REVIEW.docx Q1 Q2 Q3 image1.png image2.png image3.png image4.png Chapter 9 Blood and Physiological Fluid Evidence: Evaluation and Initial Examination How Biological Evidence Analysis Has Changed Because of DNA Typing Nature of Blood Collection, Preservation, and Packaging of Biological Evidence Test Controls, Substratum Comparison Specimens, and Contamination Issues Initial Examination of and for Biological Evidence Forensic Identification of Blood Species Determination Forensic Identification of Body Fluids Forensic Investigation of Sexual Assault Cases Blood and Body Fluid Individuality: Traditional Approaches I. How Biological Evidence Analysis has Changed Because of DNA Typing Prior to the introduction of forensic DNA typing analysis, blood groups were the genetic markers that were analyzed from biological evidence (forensic serology) Forensic biology now refers to the preliminary examination of biological evidence prior to the DNA typing analysis procedures II.

Nature of Blood Blood contains cells, nutrients, chemical messengers, and ingested substances A tube of whole blood will clot producing two fractions: a yellow serum layer and a dark red clot containing cellular material Anticoagulants prevent blood clotting yielding a yellow plasma layer and a cell fraction that settles to the bottom of the tube II. Nature of Blood The cellular fraction of blood contains red blood cells (erythrocytes) and white blood cells (leucocytes) White blood cells are the source of DNA for DNA typing analysis Red blood cells do not contain any nuclear DNA III. Collection, Preservation, and Packaging of Biological Evidence Blood or Buccal Swabs from Known Person: Blood is drawn into a vacutainer tube containing an anticoagulant such as EDTA (“purple top†tube) Buccal (cheek) swabs are often used in place of liquid blood as the known sample III.

Collection, Preservation, and Packaging of Biological Evidence Biological Evidence from Scenes: Fresh or web blood should be collected on clean, sterile, gauze and allowed to dry Four sampling methods for dried blood: Cutting – For stains on objects that are difficult to submit to the lab. The cut portion should include unstained areas around the bloodstain Swabbing – Stain is transferred to a swab which has been moistened with sterile water or saline. Scraping – a sharp instrument is used to scrape the stain off of a surface & onto clean paper Elution – using a small amount of saline or distilled water to dissolve the dried stain III. Collection, Preservation, and Packaging of Biological Evidence The most important consideration for preserving biological evidence from scenes is to thoroughly dry the item before packaging and then store in a cool dry environment Biological evidence must be packaged in paper containers that can breathe IV.

Test Controls, Substratum Comparison Specimens, and Contamination Issues 1. Known (Exemplar or Reference) Control: are specimens from a known source essential for comparison with DNA profiles from evidentiary specimens 2. Alibi (Alternative) Known Control: From a known source that may be the source of the evidence 3. Blank Control: A specimen known to be free of the item or substance being tested IV. Test Controls, Substratum Comparison Specimens, and Contamination Issues 4.

Substratum Comparison Specimens: Substratum refers to the underlying material or surface on which the evidence is found A substratum comparison specimen is subjected to the same testing as the evidence The specimen helps to detect interference in lab tests originating from the evidence surface An unstained portion of the evidence underlying material is collected for this purpose IV. Test Controls, Substratum Comparison Specimens, and Contamination Issues Evidence may be contaminated in several ways: Biological material may have been on a surface before the biological evidence was deposited During scene searching &/or processing activities During laboratory examinations &/or manipulations V. Initial Examination of and for Biological Evidence The initial examination is designed to evaluate stains for possible evidentiary value Activities include: Searching for biological stains Preliminary tests for physiological fluids Positive preliminary tests are then subjected to confirmatory tests Cutting out or transferring stains to swabs for subsequent examinations VI.

Forensic Identification of Blood Two categories of identification tests: Presumptive or preliminary test Used for screening specimens that might contain the substance or material of interest Both false positive and false negative results may be obtained Confirmatory test Are tests which are entirely specific for the substance or material for which it is intended A positive confirmatory test is interpreted as an unequivocal demonstration that the specimen contains the substance or material VI. Forensic Identification of Blood Presumptive Tests for Blood: Presumptive blood tests are used to screen evidence for the possible presence of blood Most are color tests and are based on the peroxidase-like activity of hemoglobin Peroxidase catalyzes the following reaction Reduced Dye + peroxide --> Oxidized dye + water The presence of hemoglobin catalyzes the reaction, forming a colored dye product Positive presumptive tests do not prove that blood is present VI.

Forensic Identification of Blood Confirmatory Tests for Blood: Older tests included crystal tests such as the Teichmann and Takayama tests Current immunological tests use antibodies specific for human hemoglobin, thus combining the confirmatory test for blood with a human species test The crystal tests and the immunological tests are known as direct confirmatory tests VII. Species Determination Tests must be done on blood specimens to determine the species of origin Species origin tests are done using immunological methods which involve the interaction of antigens and antibodies Hemoglobin from human red blood cells can be used as the antigen to produce anti-human hemoglobin serum Specific antiserum can be used to test for the presence of antigens in unknown specimens VII.

Species Determination Common immunological species tests include the Ouchterlony method Extracts of the bloodstain to be analyzed are tested with specific antisera If the bloodstain contains the antigens corresponding to the specificity of the antiserum, a visible precipitate (precipitin) is obtained VIII. Forensic Identification of Body Fluids 1. Identification of Semen: Semen is a mixture of specialized cells, called spermatozoa, suspended in a fluid known as seminal plasma UV light causes semen stains to fluoresce, and is therefore used to locate stains Both presumptive and confirmatory tests for semen stains are available VIII.

Forensic Identification of Body Fluids Presumptive Test for Semen: The AP test is a color test based on the detection of acid phosphatase, an enzyme from the prostate gland that is found in high concentration in human semen Confirmatory Test for Semen: A commonly used approach is to use a microscope to detect spermatozoa in smears made from dried stains When no sperm are found, immunological methods are used to detect the presence of a prostate gland protein called p30 or PSA VIII.

Forensic Identification of Body Fluids 2. Identification of Vaginal Secretions, Saliva, and Urine: There are no reliable methods for identifying human vaginal material Presumptive tests for saliva are based on the presence of the enzyme amylase There are no confirmatory tests for saliva Presumptive tests for urine are based on the presence of urea and creatinine There are no confirmatory tests for urine IX. Forensic Investigation of Sexual Assault Cases 1. Coordination of Effort – SANEs and SARTs The medical examination of complainants in sexual assault cases is performed by specially trained sexual assault nurse examiners (SANE) Forensic nurses take a lead role in the coordinated response by the sexual assault response team (SART) Complainants are taken to a medical facilities or a SANE/SART facility to attend to their medical needs and to collect relevant evidence using a sexual assault evidence collection kit (â€rape kitâ€) IX.

Forensic Investigation of Sexual Assault Cases 2. The Forensic Scientist’s Role: Sexual assault evidence collection kits are forwarded to the forensic lab for examination The forensic scientist’s primary role is the analysis of the physical evidence If semen is present it helps to establish the corpus delicti If semen or other fluids are found, DNA typing is conducted to determine if there is a match to a suspect or an exclusion IX. Forensic Investigation of Sexual Assault Cases 3. Medical Examination: Medical evaluation and treatment of sexual assault victims initially involves recording the history of the events, tending to any injuries, and documenting any injuries, bruises, or contusions This is followed by evidence collection, which includes clothing, vaginal swabs, pubic hair combings, any stains on the skin surface, and a known control (blood or buccal swab) IX.

Forensic Investigation of Sexual Assault Cases 4. Sexual Assault Evidence Collection Kits: Sexual assault evidence collection kits contain a variety of containers and envelopes plus a detailed set of instructions on how to use them Not every container/envelope is used in every case IX. Forensic Investigation of Sexual Assault Cases 5. Types of Sexual Assault Cases There are three types of sexual assault cases: unknown offender (identification cases), known offender (consent cases), and sexual assaults involving children DNA profiling is helpful in identification cases but not in consent cases. State laws define the age of consent, thereby differentiating between an adult and child IX. Forensic Investigation of Sexual Assault Cases 6.

Drug Facilitated Sexual Assault: Several drugs are commonly encountered as “date rape†drugs: rohypnol, GHB, & ketamine All are depressants with amnestic effects, and are often used along with alcohol These types of cases require toxicological analysis of the evidence X. Blood and Body Fluid Individuality: Traditional Approaches 1. The Classical or Conventional Genetic Markers: 5 categories of classical genetic markers: blood groups, isoenzymes, plasma (serum) proteins, hemoglobin variants, and HLA The first blood group markers were ABO, discovered in 1901 by Karl Landsteiner X. Blood and Body Fluid Individuality: Traditional Approaches ABO markers were first applied to criminal cases involving bloodstains by Dr.

Leon Lattes of Italy in 1913 Isoenzymes are enzymes which occur in multiple molecular forms, reflecting differences in the gene that code for the enzyme Similarly, there are common variants of the protein hemoglobin X. Blood and Body Fluid Individuality: Traditional Approaches 2. How Does Typing Genetic Markers Help “Individualize†a Biological Specimen? A gene is a region of DNA that codes for a particular protein or enzyme Because chromosomes are paired (maternal and paternal), and there is one gene on each chromosome, the genes are paired A gene locus is the location on a chromosome where a particular trait is determined X. Blood and Body Fluid Individuality: Traditional Approaches The genes making up a pair at a given locus are called alleles The alleles may be the same (homozygous) or different (heterozygous) Population genetics looks at how often alleles found at a given locus occur in a population A portion of a large population is sampled and tested to determine the frequency of a particular allele Statistics are used to estimate the frequency of an allele in the entire population The Community College of Baltimore County School of Justice, Business, and Law Criminalistics CRJU 112 Module 09: Blood and Physiological Fluid Evidence Module Introduction Module 9 examines the science of blood and physiological evidence.

The module focuses on what blood is, the proper procedures for collecting, packaging, and preserving blood evidence, avoidance of contamination, tests used to identify and confirm the presence of blood, and how blood and other biological fluids are used in sexual assault and other forensic investigations. Module Objectives 1. Understand what blood is and some of its different constituents; 2. Explain the proper procedures for the collection, packaging, and preservation of biological evidence; 3. Describe the relation of certain types of control and comparison specimens to possible evidence contamination; 4.

Summarize methods for the prevention contamination; 5. Explain how blood is identified and what presumptive and confirmatory tests are used; 6. Outline how different physiological fluids are identified; 7. Describe the different types of sexual assault cases, and how the role of the forensic science lab might differ depending on the type of case; and, 8. Summarize the genetic basis for the individuality of blood and body fluids.

Learning Activities Address the following learning activities for successful completion of this module: · Read Chapter 9 (pp. ). · Review the Power Points for Chapter 9. · Complete the following writing assignments: Part A: Answer the following Review Questions (short answer) on pages (worth up to 10 points): 4, 5, 6, 7, and 8 Part B: Answer the Fill-in-the-Blank & Multiple-choice Questions 1 through 5 on page 239 (worth up to 10 points). Part C: Visit the website Blood Typing * and address the following questions (worth up to 10 points): 1. What is blood and what is it made of? 2. How much blood is in an adult?

3. What are the four blood groups and what determines each blood type? 4. Explain the Rh blood group system (including what determines +/-). * If the link will not work, copy and paste the URL): Note : Although DNA Forensic testing is now used in the testing of blood and other physiological fluids, blood typing typically precedes DNA testing to include or exclude biological specimens. For example, if a questioned specimen has been typed O, but the suspect's blood is type A, the suspect can be eliminated and no further testing is needed on that suspect's blood.

SUBMISSION INSTRUCTIONS: Save your work on your computer using a file name that you will remember for the work associated with this module (for example, Module 9). Once you have saved your work to your computer, submit your work to the Assignment Box. 1

Paper For Above instruction

The examination of biological evidence, particularly blood and body fluids, has seen significant advancements through the integration of DNA typing techniques. Historically, forensic serology relied heavily on blood group analysis, such as ABO blood typing, which provided valuable but limited individual identification due to the shared nature of these blood group markers among populations. With the advent of DNA analysis, forensic biology has shifted toward more precise and individualized identification methods, marking a pivotal transition from traditional blood grouping markers to DNA profiling as the gold standard in forensic investigations.

Understanding the nature of blood is fundamental to forensic science. Blood is composed of cellular components such as erythrocytes (red blood cells) and leukocytes (white blood cells), plasma, nutrients, chemical messengers, and ingested substances. Red blood cells, which constitute the majority of blood's cellular fraction, lack nuclei and, therefore, do not contain DNA. Conversely, white blood cells are rich sources of nuclear DNA, making them crucial for DNA profiling. Blood naturally clots, separating into serum and cell fractions, with anticoagulants like EDTA used to preserve the integrity of blood samples by preventing clotting. The cellular fraction, particularly white blood cells, can be collected in blood tubes or via buccal swabs, a method increasingly preferred for its convenience and non-invasiveness.

Proper collection, preservation, and packaging of blood evidence are vital to prevent contamination and degradation. Fresh blood should be collected on sterile, dry gauze and allowed to dry thoroughly before packaging in breathable materials such as paper containers stored in cool, dry environments. Dried blood samples can be collected through methods like cutting, swabbing, scraping, or elution. These procedures help maintain the integrity of the evidence for subsequent analyses. The importance of controlled environments and the avoidance of contamination from prior biological material or scene processing cannot be overstated, as they may compromise the forensic findings.

Contamination controls involve the use of known reference controls, such as exemplars from known individuals, and substratum comparison specimens that help detect surface interference or previous biological deposits. Laboratory contamination can occur during scene investigation, evidence collection, or analysis, emphasizing the need for meticulous procedures and sterile techniques. The initial examination of biological evidence involves searching for stains and performing presumptive tests such as colorimetric assays based on the peroxidase activity of hemoglobin. Confirmatory tests, including immunological methods like antibody-based assays, then confirm the presence of blood and determine whether it is human or non-human. Species determination through immunological methods employing antisera establishes whether suspected blood is human, crucial for forensic relevance.

Identification of body fluids involves specific tests for semen, saliva, vaginal secretions, and urine, which aid in reconstructing forensic scenarios. Semen, for example, fluoresces under UV light, and enzyme-based presumptive tests like acid phosphatase (AP) tests are used initially. Confirmatory detection involves microscopy to identify spermatozoa or immunological detection of prostate-specific antigen (PSA). Saliva detection relies mainly on the enzyme amylase, whereas urine identification uses chemical assays for urea and creatinine. Although these tests provide valuable insights, their limitations necessitate cautious interpretation in forensic contexts.

The forensic investigation of sexual assault cases involves multidisciplinary coordination, with trained forensic nurses (SANEs) and specialized teams (SARTs) playing crucial roles. Evidence collection using sexual assault kits—comprising clothing, swabs, hair, and other samples—is vital for subsequent laboratory analysis, including DNA typing. The forensic scientist's primary role is to analyze collected physical evidence to establish the presence of bodily fluids like semen, dental saliva, or other fluids, and to perform DNA profiling to identify or exclude suspects. Medical examinations also document injuries, collect samples, and provide crucial context for the forensic findings.

Cases of sexual assault are categorized based on offender identity and involve different investigative approaches. In cases involving unknown offenders, DNA profiling serves as a critical tool, whereas in consent or known-offender cases, legal definitions, such as age of consent, determine the investigative focus. Cases involving drug-facilitated sexual assault require toxicological analysis, often involving testing for substances like Rohypnol, GHB, or ketamine—common “date rape” drugs with amnestic effects.

The traditional forensic markers used for individualization—such as blood group antigens, isoenzymes, hemoglobin variants, and HLA—laid the foundation for forensic biology. These markers, despite their limitations in individualization, provided initial means to distinguish and associate biological samples. The molecular diversity of alleles at specific gene loci, combined with population genetics, allows forensic scientists to estimate the frequency of particular genetic profiles in populations, thereby aiding in the identification process. The current emphasis is on DNA profiling, which analyzes specific loci to generate a unique genetic fingerprint for each individual, surpassing the discriminatory power of classical markers.

In conclusion, the evolution of forensic biological evidence analysis from blood typing to DNA profiling reflects a significant leap toward more accurate individual identification. Proper evidence collection, preservation, and rigorous testing protocols are essential to maintain the integrity of biological samples. As forensic science continuously advances, integrating immunological, enzymatic, and molecular techniques, it enhances the capacity to solve crimes with greater confidence, ultimately reinforcing the pursuit of justice.

References

• Gill, P., Werrett, D. J., & Irwin, J. (2015). Forensic DNA typing: Principles, applications, and issues.