DNA Fingerprinting+Gel Electrophoresis

What is DNA fingerprinting used for?

forensic evidence, identification, solving crimes, paternity disputes, etc.

What is DNA fingerprinting?

the analysis of DNA's short tandem repeats in order to identify individuals using gel electrophoresis

What specific part of DNA is analyzed in DNA fingerprinting?

short tandem repeats

What process can be used if there is only a small amount of DNA available? What does it do?

polymerase chain reaction; makes copies of the DNA so there is enough to analyze

Describe the polymerase chain reaction.

DNA is heated in order to separate the strands of DNA

short DNA primer is added to either end of the exposed strands

As the strands cool, DNA polymerase builds complementary nucleotides to the strands, making two new complementary ones

Process repeats over and over to produce many copies; DNA is repeatedly heated and cooled to copy the small amount of DNA

What agent cuts the DNA into fragments?

restrictions enzymes

What are the sections of DNA that are cut?

restriction fragments

Why could there be thousands of different-sized restriction fragments?

because each restriction enzyme is different in its name and where it cuts on the DNA sequence; some of the restriction fragments may be large while some may be short because the restriction fragments cut at different areas in the sequence

What is the process of the restriction fragments being separated called?

gel electrophoresis

DNA is injected into _______ on the __________ charged side.

wells; negatively

Why is DNA attracted to the positive end of the gel?

because it is negatively charged

Which size fragments moves the fastest in the gel?

the shorter fragments

How is DNA separated in the gel?

by SIZE, shorter fragments move faster and further

What is the advantage of using multiple restriction enzymes to cut the DNA during DNA fingerprinting?

allows the DNA to be cut into shorter fragments, which travel in the gel much faster

What percentage of DNA is the same in any two given individuals in the world? How does this play a role in STRs being used in fingerprinting?

99.9%; STRs are the short repeating sections of DNA that are unique amongst all individuals, allowing people to be identified by analyzing them

Why is electricity needed to run a gel?

the electric current causes the negatively charged DNA to migrate to the positively charged end in response, thus required to see the bars of DNA

What color is the negative electrode? Positive?

black; red

What are three ways gel electrophoresis separates molecules?

size, molecular shape, degree of charge

What is the gel made of?

agarose

Why do the shorter bars travel faster in the agarose?

because they pass through the pores in the agarose quicker due to being smaller