DNA Fingerprinting And Forensic Analysis (preparation of a DNA fingerprint…
DNA Fingerprinting And Forensic Analysis
a technique used to distinguish between individuals of the same species using sample of their DNA
also called DNA profiling, DNA testing, DNA typing oe genetic fingerprinting
inventor of DNA fingerprinting
what makes DNA fingerprinting possible?
the difference between individuals order of the base pairs in chromosomes.
every cell of an individual carries a copy of the DNA
how do we distinguish one person's DNA from another?
although 99.9% of our DNA is the same, there are short pieces called microsatellites, which repeat many times in a person's DNA.
it is the pattern of repeats that are different between individuals. these pattern of DNA sequences is the basis of DNA fingerprinting
two forms of polymorphism (variations in DNA sequence) in DNA
two important categories of tandem repeat
can be found in multiple places in the genome. also show variations in length
they are deetected using probe for the repeat
contain repeats of longer length (1 to 100bp)
occur at specific loci
count how many repeats of a specific STR at a given locus can creaete unique genetic profile
STR are repeated sequences of 1 to 6 bp that are repeated between 5 to 15 times.
homozygote- both alleles are the same length
heterozygote- alleles differ and can be resolved from one another
preparation of a DNA fingerprint
step 1. specimen collection
blood, semen, hair, saliva, body tissue cells
step 2. DNA extraction
step 3. DNA testing
restriction Fragment Length Polymorphism(RFLP)
restriction fragments are separated according to their length by gel electrophoresis.
DNA sequence detectede by breaking DNA into pieces with restriction enzymes.
Polymerase Chain Reaction (PCR)
STR amplification via PCR
applications of VNTR/STR analysis
human identity testing
which child is not likely to be the offspring of the father?
VNTR pattern is determine for as many as different loci from victim and suspects.
compare of suspects with patterns at crime scene
DNA is purified from blood
database are ssembled of VNTR?STR allele patterns from criminals
police can get blood using warrant for testing DNA
DNA can be used to clear suspects
casualities of accidents or war
diagnos of inherited disorders
developing cures for inherited disorders