BIO GENETICS

List the distances traveled in mm for the bands in the DNA ladder in the table below.
Remember, smaller fragments travel farther than longer ones, so the top-most band will be the 1,000 bp sized DNA fragments whereas the bottom-most band will be the 50 bp sized DNA fragments.

DNA Ladder
Band Distance (mm)
50 bp 90 mm
100 bp 77 mm
150 bp 69 mm
200 bp 64 mm
250 bp 60 mm
300 bp 56 mm
400 bp 51 mm
500 bp 47 mm
600 bp 43 mm
700 bp 40 mm
800 bp 38 mm
900 bp 36 mm
1,000 bp 34 mm

Whose sample had the approximately 570 bp and 320 bp sized DNA fragments?
A.F. #2
What were the sizes of the DNA fragments for alleged father #1?

41 mm 670bp

43 mm 600bp

Data Analysis
Which size DNA fragment did the child inherit from her mother?
37 mm 850bp
Which alleged father, if any, can be definitively ruled out as the child’s biological father?
A.F. #2
Conclusions
How are new molecules of DNA synthesized in living cells?

What is the function of DNA?

DNA has genetic information that controls our cells. So, DNA is like a blueprint that shows how to construct components of cells like proteins and ribonucleic acid (RNA). This information is carried down to newer generations through inheritance.

If each individual has such a small amount of DNA in their cells, how do the bands on the gel contain enough DNA to be visible?
In order to make DNA visible. The Gel has to be soaked in a dye (ethidium bromide) to bind with the DNA and rinsed off after. Ethidium bromide helps to make DNA visible by glowing brightly in UV rays.
Humans only have a few eye colors and only four ABO-based blood types. How can DNA tests definitively identify individuals when many people have brown eyes or type A blood?

Suppose a suspicious hair was found in a victim’s home. A gel is set up with the DNA fragments of two suspected criminals in lanes 4 and 5, the DNA fragments of the suspicious hair in lane 3, and the victim’s DNA fragments, as a negative control, are in lane 2. A DNA ladder is in lane 1. The resulting gel is below. Which suspect, if any, committed the crime? Explain your answer.