Question

The substitution of a T for an A in the protein coding sequence of the globin gene introduced a SNP. This SNP changed an amino acid resulting in sickle cell anemia. Unaffected individuals have the DNA sequence GAGGAG, a BseRI restriction enzyme site, in their gene generating two DNA fragments of 2 and 4 kb. The A to T substitution occurs within the BseR1 site thus inactivating the site (GTGGAG). Draw the RFLP gel including results for a carrier, as well as homozygous normal and affected individuals.

Answer 1

The wild type produces 2 and 4 kb fragments by BseR1.

But when there is mutation occur from T to A in the coding strand. Then there is not found any restriction by BseR1. And there is found the fragment size of 6 kb.

Now homozyogous wild type individual has two DNA molecules and there is found two fragments of each 2 and 4 kb on restriction by BseR1. There is found two dense band of 2 and 4 kb in the gel.

In carrier individual case, there is found one wild type DNA and another mutant type DNA. Now, there is found three bands of 6 kb, 2kb and 4 kb.

In affected case, there is found two mutant molecile. Enzyme can not digest these DNA and two fragments are found having 6 kb. These fragments are found at same position in the gel and of intense nature.

Now look in the image for gel:

UNA IMörker Norman Allected Kb Carrier a Loading well a

Please rate.