DNA Profiling in Forensic Science

Buckskin Girl

Murdered girl identified using forensic genealogy.

Forensic Genealogy

Using DNA to solve cold cases.

GEDmatch

Public genealogical database for DNA comparison.

SNP Analysis

Analyzing short DNA fragments for identification.

Degraded DNA

Damaged DNA that can still provide evidence.

DNA Profiling

Technique to identify individuals via genetic code.

Noncoding DNA

DNA sequences not coding for proteins, used in profiling.

Short Tandem Repeats (STRs)

Short DNA segments used in modern profiling.

Single Nucleotide Polymorphisms (SNPs)

Variations in a single DNA base used for analysis.

Cold Cases

Unsolved criminal cases, often reopened with new techniques.

Innocence Project

Organization exonerating wrongfully convicted individuals using DNA.

DNA Fingerprint

Pattern of DNA fragments unique to an individual.

Biological Substances

Sources of DNA evidence like blood and hair.

Identification of Remains

Using DNA to determine identity of deceased individuals.

Military DNA Storage

US military collects soldiers' DNA for identification.

Quantifiable Evidence

Scientific data used to support legal cases.

Fingerprint Analysis

Comparing unique patterns in fingerprints for identification.

Facial Reconstruction Software

Technology used to recreate faces from skeletal remains.

Blood Sample Analysis

Testing blood for DNA to identify individuals.

DNA Evidence Collection

Proper methods for gathering DNA for analysis.

Exoneration

Clearing someone of blame, often through DNA evidence.

Innocence Project

Organization that helps exonerate wrongfully convicted individuals.

DNA Fingerprinting

First forensic identification technique developed by Alec Jeffreys.

Polymorphisms

Regions of DNA with high individual variation.

CODIS

FBI database of convicted offenders' DNA profiles.

Deoxyribonucleic Acid (DNA)

Genetic material in all living organisms.

Nuclear DNA

DNA contained within a cell's nucleus.

Chromosomes

Structures of DNA tightly wrapped around proteins.

Homologous Chromosomes

Pairs of chromosomes with similar size and shape.

Gene

Basic unit of heredity composed of DNA.

Human Genome

Total DNA found in human cells.

Coding Regions

DNA segments that encode proteins.

Noncoding Regions

DNA segments that regulate protein production.

Alleles

Variations of a gene that contribute to differences.

Backlogs

Delays in analyzing DNA evidence due to testing time.

DNA Identification Act (1994)

Legislation to improve forensic labs and communication.

Contamination Rate

Frequency of DNA sample contamination affecting results.

OJ Simpson Trial

1995 case that popularized DNA evidence awareness.

Genetic Code

Sequence of nucleotides determining hereditary traits.

Base Pairs

Units of DNA made of two nucleotides.

Mitochondrial DNA

DNA located in mitochondria, inherited maternally.

Protein Coding Genes

Approximately 21,000 genes responsible for protein synthesis.

DNA Testing Duration

Typically takes 6-8 weeks for analysis.

FBI

Federal Bureau of Investigation, involved in DNA profiling.

DNA Isolation

Extracting DNA from cells for analysis.

PCR

Polymerase Chain Reaction to amplify DNA.

Electrophoresis

Technique to separate DNA fragments by size.

STRs

Short Tandem Repeats, DNA fragments under 50 bases.

Variable Regions

Non-protein coding areas with high DNA variability.

Markers

Specific locations on chromosomes for STR identification.

Introns

Non-coding DNA regions containing STR sequences.

Core STR Markers

13 specific STRs used by the FBI.

AMEL Marker

Determines sex of DNA source, male or female.

D18551 Marker

Highly variable STR on chromosome 18.

Homozygous Genotype

Two identical alleles for a specific STR.

Heterozygous Genotype

Two different alleles for a specific STR.

Allele Frequency

Occurrence of an allele in a population.

Probability Calculation

Determining likelihood of matching DNA profiles.

DNA Evidence Preservation

Proper documentation and packaging of DNA samples.

FBI STR Expansion

Addition of 7 STR markers in 2017.

STR Profile

Representation of inherited STR alleles as numbers.

Crime Scene DNA

Degraded DNA often recovered as STRs.

Allele Inheritance

Child inherits one allele from each parent.

Electrophoresis Fingerprint

Visual representation of DNA fragment separation.

Documentation of Evidence

Essential for maintaining integrity of DNA samples.

Automated Procedures

Modern methods replacing traditional gel electrophoresis.

Nuclear DNA

Found in white blood cells and skin cells.

PCR Process

Amplifies DNA samples for analysis.

Contamination

Mixing relevant DNA with foreign DNA.

Disposable Gloves

Worn to prevent contamination during evidence collection.

DNA Evidence Precautions

Steps to avoid contamination during collection.

Moisture Impact

Humidity encourages mold growth, damaging DNA.

Y-STR Analysis

Traces ancestry through the male lineage.

mtDNA Analysis

Analyzes maternal lineage using mitochondrial DNA.

DNA Fingerprinting

Identifies individuals using unique DNA patterns.

CODIS

Combined DNA Index System for DNA profiles.

DNA Profiles

Stored for convicted individuals of serious crimes.

DNA Evidence Storage

Keep dry, cool, and out of sunlight.

Electrophoresis

Technique for separating DNA fragments by size.

DNA Amplification

Increasing DNA quantity for analysis.

Non-coding Regions

Areas of DNA with repeated sequences.

Bite Marks

Potential source of DNA evidence.

Hypervariable Regions

Noncoding regions compared in mtDNA analysis.

Victim Identification

Using DNA to identify disaster victims.

Genetically Modified Crops

Tracked using DNA fingerprinting techniques.

Immigration Disputes

Settled using DNA paternity testing.

Class Evidence

Links evidence to a family lineage.

Biotechnology Advances

Improved DNA profiling over the last 25 years.