Presentation Transcript
DNA Fingerprinting Using PCR :DNA Fingerprinting Using PCR Timothy G. Standish, Ph. D.
Polymorphism :Polymorphism Differences between humans can be attributed to two factors:
Environmental variation impacting development
Individual genes that vary between people
These genes which are variable are called polymorphic
Each person is genetically unique because of their unique set of polymorphic genes
All people are related in that the vast majority of their genes do not vary, but are identical from person to person
DNA Fingerprinting :DNA Fingerprinting DNA fingerprinting involves identification of DNA segments which vary between individuals
A set of DNA fragments polymorphic enough to provide a unique set of fragments for all individuals, can be used to identify any specific individual in a population
No single fragment will uniquely identify an individual, just as no single polymorphic genetic trait will uniquely identify a person, but a unique set of polymorphic DNA traits/fragments can serve as a reliable means of identification
Polymorphism In The TPA Gene :Polymorphism In The TPA Gene Tissue Plasminogen Activator (TPA) is a protein that functions in the cascade of reactions which break down blood clots
The gene contains 14 exons and 13 introns
Scattered within the introns are 28 Alu transposon sequences
Within intron 8 a single Alu sequence may be present, or it may be missing
Thus, as intron 8 varies with the presence or absence of Alu, it is polymorphic
Polymorphism In The TPA Gene :Polymorphism In The TPA Gene
PCR Detection of TPA Polymorphism :PCR Detection of TPA Polymorphism PCR will produce a 660 bp fragment 300 base pairs PCR will produce a 660 bp fragment if these primers are used
Components of a PCR Reaction :Components of a PCR Reaction Buffer (containing Mg++)
Template DNA
2 Primers that flank the fragment of DNA to be amplified
dNTPs
Taq DNA Polymerase (or another thermally stable DNA polymerase)
PCR :PCR
PCR :PCR 3’ 5’ Heat
PCR :PCR
PCR :PCR Heat Heat 5’
PCR :PCR
PCR :PCR Heat Heat
PCR :PCR
PCR :PCR
DNA Between The Primers Doubles With Each Thermal Cycle :DNA Between The Primers Doubles With Each Thermal Cycle
PCR Detection of TPA Polymorphism :PCR Detection of TPA Polymorphism PCR will produce a 660 bp fragment 300 base pairs PCR will produce a 660 bp fragment if these primers are used
Gel Electrophoresis :Gel Electrophoresis