DNA

Mid-1980s

DNA fingerprinting dramatically changed forensic science and the ability of law enforcement to link perpetrators with crimes

Early 1990s

The US military began collecting and storing blood samples of soldiers

1994

DNA identification act

1998

National DNA index system NDIS

CODIS

The combined DNA index system collects analyzes, and communicates criminal DNA information

DNA

Deoxyribonucleic acid

What is DNA

the genetic material of all living things

Chromosomes

the 46 chromosomes found in the human body cells are composed of tightly coiled DNA

male chromosomes

have one X and on Y chromosomes (XY)

Female Chromosomes

have two X chromosomes (XX)

DNA Inherit

Half of our DNA is inherited from our mother, and the other half is inherited from our father

how many pairs of Karotypes

There are 22 pairs of homologous chromosomes in males and Autosome pairs of homologous chromosomes in females.

What are genes

A gene is a segment of DNA in a chromosome that serves in the prodution or regulation of proteins

What do genes average

3000 base pairs

Dna evidence is what?

Critical

what should you void when collecting, preserving and identifying

Contamination

PCR traces samples of what so that it can be amplified so that adequate amounts are available for testing

DNA Evidence

The most useful tool for law enforcement since the development of fingerprinting

DNA profiling

Scientist use this to distinguish one person from another

polymorphisms

Because 99% of all human DNA is the same scientst only need to examine what percent

1% region of variability

When does a heterozygous genotype occur

When a person has two different alleles for a particular STR

What Does STR stand for

Short Tandem Repeats

STR’s can easily be recovered from what

Degraded and limited quantites of DNA typically found for evidence

How is DNA STR analysis performed

Using automated machines and computers

Y STR’s

Trace ancestry through the male line

mtDNA

Only mother pass on mitochondrial DN

mtDNA & Y STR’s

Can only yield class evidence

DNA sequences are?

Unique to each individual

DNA analysis

Helps solves crimes and exonerate the falsely accused

Adding fluorescent dyes to the PCR reaction makes it possible to identify what?

Different STR markers