Student Exploration:

DNA Profiling

Vocabulary: DNA polymerase, DNA profiling, gel electrophoresis, gene, mutation, non-coding

region, polymerase chain reaction, primer, short tandem repeat

Gizmo Warm-up

DNA profiling does not just compare people’s entire genome side

by side. Instead, a very particular part of the DNA is compared. In

the DNA Profiling Gizmo you will learn about the differences in

DNA that make DNA profiling possible and you will use that

knowledge to design your own DNA profiling test.

Click on the crime lab in the Forensic training section. You are looking at a strand of DNA at the top of

the screen. DNA contains genes and non-coding regions between genes. Click on

Non-coding A.

1. You are looking at a portion of the non-coding A section for three different people. Are these

sections the same or different? [The three individual strands are the same up until the 14th

code.] Explain. [Person number 2 only has 2 STRs while person number 1 has 4 and person

number 3 has 3, making the sections different.] (you may want to click on “Show STR”)

2. Click Previous then click on Gene A. Are there differences in gene A for the three people?

[yes] Why do you think the coding Gena A are different or all the same for the 3 people? [ I think

they are different because person 2’s sequence of nucleotides has a mutation. Since they

are all coding for the same gene the sequence should be identical, unless there is a

mutation, which is found in person 2.]