Podcast
Questions and Answers
How many publicly funded crime laboratories are operating in the United States?
How many publicly funded crime laboratories are operating in the United States?
400
What are examples of Trace Evidence?
What are examples of Trace Evidence?
What is the most common source for narcotic drugs?
What is the most common source for narcotic drugs?
Opium
The most common type of fingerprint is a loop.
The most common type of fingerprint is a loop.
Signup and view all the answers
What is the process of releasing DNA from a cell called?
What is the process of releasing DNA from a cell called?
Signup and view all the answers
How many core loci does CODIS have?
How many core loci does CODIS have?
Signup and view all the answers
What is the name of the protein found in seminal plasma?
What is the name of the protein found in seminal plasma?
Signup and view all the answers
What are the two specific segments of the control region on the DNA Loop?
What are the two specific segments of the control region on the DNA Loop?
Signup and view all the answers
Which of the following drugs are depressants?
Which of the following drugs are depressants?
Signup and view all the answers
What is the most widely used approach for determining alcohol levels in blood?
What is the most widely used approach for determining alcohol levels in blood?
Signup and view all the answers
What is the legal term for any penetration by a sex organ or any object without consent?
What is the legal term for any penetration by a sex organ or any object without consent?
Signup and view all the answers
What are examples of presumptive tests used to detect the presence of blood?
What are examples of presumptive tests used to detect the presence of blood?
Signup and view all the answers
A single Y-STR profile will have two peaks at each locus.
A single Y-STR profile will have two peaks at each locus.
Signup and view all the answers
A large gene pool is associated with poor genetic diversity.
A large gene pool is associated with poor genetic diversity.
Signup and view all the answers
The most common source of extraneous DNA is from the investigators themselves.
The most common source of extraneous DNA is from the investigators themselves.
Signup and view all the answers
The forensic scientist uses ______ to determine the rarity of a specific DNA profile in a relevant population.
The forensic scientist uses ______ to determine the rarity of a specific DNA profile in a relevant population.
Signup and view all the answers
Which of the following are used as presumptive tests to detect the presence of semen?
Which of the following are used as presumptive tests to detect the presence of semen?
Signup and view all the answers
What substance is used to develop latent fingerprints on a non-porous surface?
What substance is used to develop latent fingerprints on a non-porous surface?
Signup and view all the answers
The Quantifiler® kit quantifies the total amount of amplifiable DNA by targeting the hTERT gene.
The Quantifiler® kit quantifies the total amount of amplifiable DNA by targeting the hTERT gene.
Signup and view all the answers
The process of separating amplified DNA based on the number of repeats is called PCR amplification.
The process of separating amplified DNA based on the number of repeats is called PCR amplification.
Signup and view all the answers
What is the name the tool used in DNA analysis to separate DNA fragments?
What is the name the tool used in DNA analysis to separate DNA fragments?
Signup and view all the answers
What is the name of the forensic DNA database used by the FBI?
What is the name of the forensic DNA database used by the FBI?
Signup and view all the answers
The analyst can fully discriminate between unrelated individuals using Y-STR markers.
The analyst can fully discriminate between unrelated individuals using Y-STR markers.
Signup and view all the answers
What type of DNA is used for samples such as hair, where STR analysis may not be possible?
What type of DNA is used for samples such as hair, where STR analysis may not be possible?
Signup and view all the answers
What are two common commercial kits used for STR amplification?
What are two common commercial kits used for STR amplification?
Signup and view all the answers
Which of the following are methods used to quantify DNA?
Which of the following are methods used to quantify DNA?
Signup and view all the answers
What is the name of the software used to deconvolute DNA samples and calculate statistics?
What is the name of the software used to deconvolute DNA samples and calculate statistics?
Signup and view all the answers
What are three common databases used in CODIS?
What are three common databases used in CODIS?
Signup and view all the answers
The Bayesian approach is used for determining the probability of an event given that a specific event has occurred.
The Bayesian approach is used for determining the probability of an event given that a specific event has occurred.
Signup and view all the answers
The Bayesian approach takes into account the number of contributors to a DNA profile.
The Bayesian approach takes into account the number of contributors to a DNA profile.
Signup and view all the answers
The fully continuous model uses computer algorithms to simulate data based on a known number of cycles.
The fully continuous model uses computer algorithms to simulate data based on a known number of cycles.
Signup and view all the answers
What is the term for the process of reviewing analyst reports for technical accuracy?
What is the term for the process of reviewing analyst reports for technical accuracy?
Signup and view all the answers
What type of DNA analysis is used to predict physical characteristics from genetic information?
What type of DNA analysis is used to predict physical characteristics from genetic information?
Signup and view all the answers
Forensic genealogy uses public genealogy databases to develop investigative leads in criminal cases.
Forensic genealogy uses public genealogy databases to develop investigative leads in criminal cases.
Signup and view all the answers
Mendel's Second Law states that the segregation of each allele pair is independent of the other alleles.
Mendel's Second Law states that the segregation of each allele pair is independent of the other alleles.
Signup and view all the answers
The Hardy-Weinberg Principle predicts how gene frequencies will change in a population, given that there is no genetic drift, mutation, selection, or migration.
The Hardy-Weinberg Principle predicts how gene frequencies will change in a population, given that there is no genetic drift, mutation, selection, or migration.
Signup and view all the answers
What is the name of the equation used to determine a person’s BAC using information about the type of beverage, weight, and gender?
What is the name of the equation used to determine a person’s BAC using information about the type of beverage, weight, and gender?
Signup and view all the answers
The horizontal gaze nystagmus test is considered a reliable and effective psychophysical test.
The horizontal gaze nystagmus test is considered a reliable and effective psychophysical test.
Signup and view all the answers
The ratio of alcohol in the blood to alcohol in alveolar breath is 2,100 to 1.
The ratio of alcohol in the blood to alcohol in alveolar breath is 2,100 to 1.
Signup and view all the answers
What are common types of cases that involve DNA analysis?
What are common types of cases that involve DNA analysis?
Signup and view all the answers
The process of producing multiple copies of DNA to characterize it is called Electrophoresis.
The process of producing multiple copies of DNA to characterize it is called Electrophoresis.
Signup and view all the answers
A DNA profile by itself is very informative and can often lead to immediate identification of suspects.
A DNA profile by itself is very informative and can often lead to immediate identification of suspects.
Signup and view all the answers
A locus that displays only one peak indicates that the individual inherited the same allele from each parent.
A locus that displays only one peak indicates that the individual inherited the same allele from each parent.
Signup and view all the answers
The presence of more than two alleles at a single locus always indicates a mixture of DNA from multiple contributors.
The presence of more than two alleles at a single locus always indicates a mixture of DNA from multiple contributors.
Signup and view all the answers
A higher LR is typically obtained when evaluating a true contributor, compared to a noncontributor to a DNA sample.
A higher LR is typically obtained when evaluating a true contributor, compared to a noncontributor to a DNA sample.
Signup and view all the answers
An analyst can interpret a DNA profile as inconclusive whenever there are artifacts and extraneous peaks in the electropherogram.
An analyst can interpret a DNA profile as inconclusive whenever there are artifacts and extraneous peaks in the electropherogram.
Signup and view all the answers
A criminal offense must have occurred in order for a DNA profile to be eligible for inclusion in CODIS.
A criminal offense must have occurred in order for a DNA profile to be eligible for inclusion in CODIS.
Signup and view all the answers
Which of the following are considered as extraneous peaks in a DNA profile? (select all that apply)
Which of the following are considered as extraneous peaks in a DNA profile? (select all that apply)
Signup and view all the answers
What is the scientific term for the process of adding nucleotides to a DNA strand to replicate it?
What is the scientific term for the process of adding nucleotides to a DNA strand to replicate it?
Signup and view all the answers
The process of separating amplified DNA by size using an electric current is called Electrophoresis.
The process of separating amplified DNA by size using an electric current is called Electrophoresis.
Signup and view all the answers
A high dose hook effect can result in a false negative result during a HemaTrace test for the presence of human blood.
A high dose hook effect can result in a false negative result during a HemaTrace test for the presence of human blood.
Signup and view all the answers
What type of substance is commonly found in sweat?
What type of substance is commonly found in sweat?
Signup and view all the answers
The purpose of forensic serology is to analyze for the presence of various body fluids.
The purpose of forensic serology is to analyze for the presence of various body fluids.
Signup and view all the answers
In what year did the FBI launch IAFIS, the Integrated Automated Fingerprint Identification System?
In what year did the FBI launch IAFIS, the Integrated Automated Fingerprint Identification System?
Signup and view all the answers
What is the name of the forensic scientist who developed the antibody test for determining blood type from a dry sample?
What is the name of the forensic scientist who developed the antibody test for determining blood type from a dry sample?
Signup and view all the answers
Prior to the use of DNA technology, bloodstains were linked to a source by ABO typing and the characterization of polymorphic blood enzymes and proteins.
Prior to the use of DNA technology, bloodstains were linked to a source by ABO typing and the characterization of polymorphic blood enzymes and proteins.
Signup and view all the answers
What is the most common stain used to visually confirm the presence of semen?
What is the most common stain used to visually confirm the presence of semen?
Signup and view all the answers
Study Notes
Forensic Science Introduction
- Forensic science applies scientific methods to criminal and civil cases, often by police agencies.
- It involves methodical collection, analysis, and presentation of evidence for legal proceedings.
Misconceptions about Forensics
- A common misunderstanding is that forensic science is synonymous with "CSI."
- The actual field involves a methodical approach to scientific investigation of evidence.
A Day in the Life of a Forensic Scientist
- Includes crime scene investigation and handling evidence.
- Collaboration with crime scene investigators.
- Documentation of findings.
- Testifying in court.
Branches of Forensic Science
- Criminalistics: Focuses on the recognition, collection, identification, individualization and interpretation of physical evidence.
- Forensic Science: Encompasses the application of science to criminal and civil laws.
Key Figures in the Development of Forensics
-
Sir Arthur Conan Doyle: Popularized crime detection methods through Sherlock Holmes's character.
-
Mathieu Orfila: Considered the "father of forensic toxicology" for his work on detecting poisons.
-
Eugene Vidocq: Founded the Brigade de la Sûreté, a plain-clothes investigative unit, and advocated for a criminal database.
-
Alphonse Bertillon: Researched biometrics, and developed a system (known as anthropometry) to identify criminals through detailed measurements.
-
Sir Francis Galton: Conducted the first definitive study of fingerprints and their classification, providing scientific proof for their uniqueness.
-
Leone Lattes: Developed a procedure for determining blood type from dried bloodstains.
-
Calvin Goddard: Established the comparison microscope as a tool for firearm identification.
-
Albert S. Osborn: Developed fundamental principles of document examination, with his book Questioned Documents.
-
Walter C. McCrone: Introduced applications of microscopy to analytical problems, particularly forensic science.
-
Hans Gross: Recognized as the "founding father" of criminal profiling, emphasizing the role of various scientific fields in criminal investigations.
-
Edmond Locard: Created the first crime lab and established the principle of "every contact leaves a trace."
-
Sir Alec John Jeffreys: Invented DNA fingerprinting.
Locard's Exchange Principle
- "Every contact leaves a trace."
- Exchange of materials occurs when two objects come into contact.
Crime Laboratory
- History: Characterized by rapid growth and a lack of comprehensive planning.
- Types: Federal, state, county, and municipal levels.
- Composition: Can be part of police departments, medical examiners' offices, or stand alone.
Forensic Disciplines
- Chemistry: Identifies and compares physical evidence (including controlled substances and trace evidence from the scene)
- Biology: Investigates body fluids.
- Firearms: Investigates discharged bullets, cartridge cases, and ammunition
- Document: Conducts handwriting analysis and examines questioned documents.
- Photography: Applies specialized photographic techniques for recording and examining physical evidence.
- Toxicology: Examines body fluids and organs for drugs and poisons.
- Latent Fingerprints: Processes and examines evidence for latent fingerprints.
Forensic Databases
- IAFIS: Integrated Automated Fingerprint Identification System. A national database maintained by the FBI, for fingerprint identification.
- CODIS: Combined DNA Index System. A database of DNA profiles, from the FBI that help link crimes
- NIBIN: National Integrated Ballistics Information Network. A database for firearm identification.
- PDQ: Paint Data Query. A database that provides information for the identification and comparison of automotive and architectural paints.
Forensic Data Collection - The Crime Scene
- Step 1: Establishing the scene: Recognizing and managing potential safety hazards, such as chemical or biological contamination.
- Step 2: Establishing security: Establishing crime scene perimeters, documenting entry/exit, and managing personnel access.
- Step 3: Planning/Communication/Coordination: Develop strategies/procedures, including calling specialist personnel.
- Step 4: Survey Walkthrough: Documents the scene as-recovered, prior to any collection.
- Step 5: Documenting/Processing the Scene: Document evidence types, collection method/sequence and their location. Photographic and sketching must be included.
- Step 6: Collecting/Preserving Evidence: Documenting the location of evidence, marking and appropriately packaging. Establishing the chain of custody through an inventory log, preserving the integrity of the evidence.
- Step 7: Final Survey: Reviewing the process, documenting the items and the locations of evidence collected, for confirmation, before releasing the scene.
Forensic Analysis
- Physical Evidence: Tangible objects that can connect a suspect to a crime scene.
- Direct Evidence: Provides a definitive conclusion or direction; uses deductive reasoning.
- Circumstantial Evidence: Provides leads that may be relevant in case; uses inductive reasoning.
Forensic Databases
- IAFIS: Integrated Automated Fingerprint Identification System.
- CODIS: Combined DNA Index System
DNA Profiling
-
DNA: Deoxyribonucleic acid, a large molecule containing the genetic code.
-
Chromosomes: Structures in the cell containing genetic material.
-
Genes: Units of genetic information that contain the instructions for protein production.
-
Alleles: Different forms of the same gene.
-
VNTRs: Variable number tandem repeats. Repeating bases in non-coding regions; provide high discriminatory power.
-
STRs: Short tandem repeats. DNA sequences that contain short, simple repeating patterns, more stable during degradation and can be amplified by PCR.
-
PCR: Polymerase Chain Reaction. A technique for replicating segments of DNA exponentially, useful in forensic scenarios allowing for amplification from small sample quantities.
-
Electrophoresis: A technique to separate DNA fragments based on size, using a gel or capillary and an electric field.
Types of DNA Analysis
- STR Analysis: Examining short tandem repeats in DNA to produce a unique profile for comparison.
- RFLP (Restriction Fragment Length Polymorphisms): Identifying DNA fragments of varying lengths based on restriction enzymes. This technique has been replaced by simpler methods.
- Mitochondrial DNA (mtDNA): Analyzing the DNA in mitochondria, inherited from the mother. Useful when dealing with degraded/limited DNA quantity, where STR analysis is not possible.
- Y-STR Analysis: Analyzing Y-chromosome-specific STRs. Useful in cases with male DNA mixtures, including sexual assault cases, to trace likely related male individuals.
- Analysis for Mixture Profiles- used in situations where DNA from more than one person is present in a sample.
Forensic Application of DNA
- Forensic Database: A database that keeps convicted offender's DNA profiles and allows for comparison.
- Databases: The FBI's CODIS (Combined DNA Index System), an international database for DNA profiles from convicted felons (offenders) and unsolved crimes and missing persons in the United States.
- Crime Scene: Samples are considered as biological evidence such as blood, saliva, hair, semen, etc., which undergo various steps such as extraction, quantitation, PCR amplification, and electrophoresis for identification.
Forensic Toxicology
- Introduction: The analysis of the substances in bodily fluids and tissues for detecting and identifying drugs and poisons.
- Alcohol Analysis: The most common forensic toxicology test, requiring measuring alcohol in bodily fluids often via blood and urine samples.
- Common Forensic Toxicology Tests: Presumptive and confirmatory tests.
- Significance of findings: Provides information or opinions about the suspected behaviour of the individual in the drug-induced process, considering individual variability of factors, including age, health, and tolerance and circumstances of testing.
- Cases involving the use of other substances: Cases involving drug overdose or other intoxications.
Forensic Serology
- Forensic serology is the science employed to detect the presence of body fluids (e.g., blood and semen) and their characteristics for criminal investigations.
- Blood analysis involves tests (including presumptive and confirmatory tests) for identifying blood origin and blood type.
- Semen analysis involves visual examination under alternate light sources, confirmatory microscopy, and DNA typing for identifying and linking semen to the individual who produced it.
- Presumptive test: Indicates the presence of a substance.
- Confirmatory test: Confirms the presence of a specific substance.
Additional points
- Note-taking, documentation, and case filing are essential aspects of forensic procedures.
- Quality assurance ensures accuracy and that the procedures adhered with are precise.
- Emerging technologies may improve case procedures and analysis.
- Relevant legislation and laws can be used as guidelines for procedure.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
