A crime scene investigation was able to collect a minute quantity of DNA found in a saliva sample left on a drinking cup where the stabbing occurred earlier that day

A crime scene investigation was able to collect a minute quantity of DNA found in a saliva sample left on a drinking cup where the stabbing occurred earlier that day. Below you will find data developed at the crime lab that analyzed the status of the noncoding regions in the suspect’s DNA.

a. For this question, please consult the illustration below.

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a. At the TH01 locus on both #11 chromosomes, the following number of repeats were found. (The STR sequence at the TH01 locus is AATG).

On one of the two #11 chromosomes, the following number of repeats was found.

AATG AATG AATG AATG AATG

And on the other #11 chromosome, the following number of repeats was found.

AATG AATG AATG AATG AATG AATG AATG AATG

How would these numbers be reported in a DNA profile of the TH01 locus?

b. Why are noncoding regions used in forensic science instead of mapping the coding areas of DNA?

c. In the following diagram, after using PCR to make billions of copies of the noncoding sequence of the VWA locus on chromosome #12, the sample was then added to the well of a gel electrophoresis apparatus. The electric current was turned on and the sample was separated into two separate bands labeled as #1 and #2 below.

Why did the noncoding DNA samples from both #12 chromosomes produce two bands and not one?

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d.. If only one band had been produced from the noncoding regions of both #12 chromosomes, what would that have inferred about the number of repeats in the VWA locus on both chromosomes?