CODIS – Combined DNA Index System

CODIS STRs and ProbabilitySTR African

AmericanAmerican Caucasian

D351358 0.097 0.080

VWA 0.074 0.068

FGA 0.036 0.041

TH01 0.114 0.080

TPOX 0.091 0.207

CFS1PO 0.079 0.128

D5S818 0.121 0.166

D13S317 0.139 0.081

D7S820 0.087 0.067

D8S1179 0.080 0.069

D21S11 0.042 0.041

D18S51 0.032 0.032

D16S539 0.076 0.091

1/X = value

1/X = 0.097

SOLVE FOR X

X = 1/0.097 = 10.3

This means the DNA matches one in 10.3 people

Think about class evidence…how do we narrow down the pool of

possible suspects?

Where is DNA found?

DNA is contained in blood, semen, skin cells, tissue, organs, muscle, brain cells, bone, teeth, hair, saliva, mucus, perspiration, fingernails, urine, feces, etc.

http://www.dna.gov/basics/

THIS IS NUCLEAR DNA!

Two types of DNA

Analysis of mtDNA is done when RFLP and STR cannot be used on NUCLEAR DNA

1. Nuclear DNA (inside nucleus)

2. Mitochondrial DNA (mtDNA)

Nuclear DNA

Nuclear DNA:Found in nucleus of cellsContains 23 chromosome pairsEach parent contributes half

Mitochondrial DNA

Mitochondria are found in all cells of the body

Provides 90% of energy our bodies need to function

Contain bits of DNA passed down through generations

Hundreds of thousands of mitochondria per cell!!

What are the benefits? What are the limitations?

Nuclear vs. Mitochondrial DNA

Mitochondrial DNA

Used in identifying remainsGenerous amount present in bonesShows maternal lineage matches (will be

identical if related through the mother)

In the NEWS: Sandringham http://www.metro.co.uk/news/886331-sandringham-murder-body-could-be-

missing-teenager-say-police http://www.telegraph.co.uk/news/uknews/crime/8998481/Sandringham-body

-identification-will-take-further-three-days.html

Last March

Royalty-obsessed Robert James Moore found dead

TOD ~ up to 3 yrs

Missing Persons: Dung Beetle Biologist