Genetic Fingerprinting Flashcards
What is genetic fingerprinting?
A technique used by scientists to identify the unique sequence of genes in an individual.
What is a core sequence?
A section of blocks of repeated nucleotides in introns
When comparing sequences of DNA from 2 organisms, what can we assume if the core sequences are similar?
They are more closely related.
Why might DNA be amplified using PCR before sequencing occurs?
The DNA sample could be very small
How can DNA be extracted from cells before sequencing occurs?
Cells are broken to release DNA.
DNA cut into fragments using restriction endonucleases.
What is a restriction fragment?
A sample of DNA that has been cut
Describe how DNA can be separated using gel electrophoresis.
DNA injected into wells surrounded by agar gel and an electric current is supplied.
DNA diffuses down the gel as it attracts to the positive end of the gel
Why is DNA able to diffuse down the gel in electrophoresis?
DNA is negatively charged, so attracts to the positive terminal.
Describe how size of the DNA fragment influences how quick it moves.
Smaller DNA fragments move faster.
What are the bands seen in gel electrophoresis representative of?
Size of the fragments.
Why is the gel immersed in alkali after the DNA has separated into bands?
To separate the double strands into single strands
Name the material that the membrane is made from when patterns of the fragments are transferred to it.
Nylon
How are DNA fragments fixed to the nylon membrane?
UV light
What is used to attach core sequences to the nylon membrane in gel electrophoresis?
Radioactive probes which are complimentary to the core sequences.
What happens to DNA probes that have not bound to the nylon membrane?
They are washed off
