RFLP's & Gel Electrophoresis

Question 1

what does gel electrophoresis do

Answer 1

separates pieces of DNA (and RNA and proteins) by size and is used in many industries for different purposes: DNA fingerprinting & research

Question 2

define DNA fingerprinting + 3 examples

Answer 2

matching individuals or finding how related they are
ex: paternity testing, analyzing crime scenes, evolutionary bio, etc

Question 3

define research

Answer 3

to isolate + study genes, proteins, etc

Question 4

what is the use of restriction enzymes

Answer 4

used to digest (cut up) a piece of DNA up into smaller pieces

Question 5

the number and size of pieces that result are different for each individual, why?

Answer 5

because the non-coding areas of DNA are different from individual to individual in terms of size, sequence, numbers of repeating segments

Question 6

what are polymorphisims

Answer 6

each individual has a unique combination of polymorphisisms inherited from their parents
- short, repeating sequence (20 - hundreds of times)

Question 7

what does RFLP stand for

Answer 7

Restriction Fragment Length Polymorphism

Question 8

what is RFLP

Answer 8

refers to the fact that, after being digested by a certain enzyme, each individual will show a different number of fragments with different sizes, allowing us to obtain a “DNA fragment” and identify specific people

Question 9

how it works

Answer 9

1. a tray is filled with a gel made of agarose (comes from seaweed) and a buffer solution
2. the DNA samples are loaded into small holes called “wells” at one end of the gel’ with one being used for the DNA ladder/control - it contains pre-known fragments sizes and will be used to determine the sizes of fragments in your sample
3. due to the phosphate groups in the DNA backbones, DNA is negatively charged. the gel will be hooked up to a power supply which will charge the end near the wells negatively, and the other end positively. This difference in charge pulls the DNA through the gel.
4. DNA of different sizes will go faster or slower. larger segments move slower and remain closer to the negative end (start point), smaller pieces move faster and farther and end up near the positive end

Question 10

analyzing the results

Answer 10

identical chromosomes (such as the matching chromosome receives from a parent) will chop up the same way
so half of an individuals DNA fingerprint should match parts of their mothers, and the other half should match parts of their fathers. other relatives (siblings, cousins, etc) will have matching sections. the more closely related two people are, the more their DNA fingerprints will be similar
in forensics, this allows us to determine if a person was at a crime scene (if DNA samples taken from the scene match the suspect, it allows us to determine relatedness between different species or match them to identify certain diseases ( inherited or cancer, etc)