Forensics DNA Profiling

Indirect individual evidence

DNA is what type of evidence

99%

What percent of all human DNA is identical

Person’s DNA profile

Pattern of DNA fragments, we analyze the noncoding sequences of DNA

Required for DNA to be valid

Proper collection, documentation, and processing

Nucleotide

Monomer of DNA

Adenine, guanine, cytosine, thymine

4 nitrogen bases of DNA

Sugar, phosphate, nitrogen base

3 parts of DNA structure

Gene

Segments of DNA/parts of chromosome that code for a specific trait

Exons

Code for proteins

Introns

Noncoding regions used to create DNA profiles

Polymerase chain reaction

Amplifies the amount of DNA in a sample

Short tandem repeats (STRS)

Pattern of repeated bases with 20 areas/loci used in DNA analysis

Gel/capillary electrophoresis

Methods to analyze STRs

Gel electrophoresis

Fragments of DNA are cut and placed in gel

Electric current applied, causing migration of DNA

Longer fragments remain near the top and smaller fragments move close to the bottom

Want all bands to match when DNA profiling

Electrophoresis

Movement of charged particles through a medium

Electropherogram

Location and pattern of peaks creates a DNA profile

STR loci are named

Number below peak - number of repeats

DNA contamination

DNA from outside source mixes with DNA sample that is being analyzed

Collection and preservation of DNA

Wear disposable gloves, disposable instruments, avoid touching areas DNA might be, wear a mask, air dry/freeze possible DNA evidence, separate items to package

Touch DNA

Minute amounts of DNA from skin cells, sweat, or bodily fluids left on surfaces

Forensic investigative genetic genealogy

Application of genetics to traditional genealogy

Create a family tree using vital records around an unknown DNA profile

Uses public databases

DNA phenotyping

Technique that analyzes DNA to predict physical appearance

Identifying human remains, DNA Doe project