genetic finger printing

Question 1

what is the difference between exons and introns

Answer 1

1) regions of DNA that code for proteins

2) regions of DNA which are non-coding

Question 2

outline how introns are used in genetic fingerprinting

Answer 2

1) Introns are made up of 3-5 nucleotide sequences repeated many times eg GATAGATAGATA
2) this is known in DNA as short tandem repeats whose length varies from individual to individual
3) humans acquire different length sequences from parental chromosomes
4) the maternal will provide one specific length whilst the paternal will provide a another specific short tandem repeat so each child has 2

Question 3

what is genetic fingerprinting

Answer 3

the analysis of the number of times these lengths of non-coding DNA are repeated to show differences between individuals

Question 4

outline the method of genetic fingerprinting

Answer 4

1) DNA is extracted from a sample and cut with restriction enzymes at specific base sequences on either side of the STR
2) DNA, therefore, is cut into fragments of different lengths depending on the length of the STR
3) fragments are separated using gel electrophoresis’s where negatively charged fragments move towards the positive electrode
4) smaller fragments move faster and further than larger ones creating a banding pattern

5) the gel is treated with an alkaline solution to separate DNA into single strands and the gell is the combined with a nylon membrane where DNA fragments are transferred
6) they are exposed to radioactive solutions where probes attach to specific single-stranded STRS
7) then placed under x-ray film to form an autoradiograph of different light and dark bands, dark showing Probe present,
8) the pattern is unique to an individual and is the genetic fingerprint

Question 5

where can genetic finger printing be applied

Answer 5

1) paternity suits

2) criminal convictions

Question 6

what are the advantages of DNA profiling

Answer 6

1) non-invasive
2) can be used on small DNA samples
3) can be used to reverse wrongful convictions

Question 7

what are the disadvantages of DNA profiling

Answer 7

• access must be carefully regulated

- employers may avoid hiring individuals who have certain genetic traits