Question

Deamination in which nucleoside can have more deleterious effects on the genome?

Select one:

a. Thymidine

b. Cytidine

c. Deoxythymidine

d. Deoxycytidine

e. Deoxyguanosine

Clear my choice

Answer 1

Deamination or removal of an amino group occurs in the NTPs that carry an amino group. In human genome, deamination of deoxycytidine in a DNA strand is carried out by cytidine deaminase, resulting in a deoxyuridine. Deoxyuridine pairs in a non-complementary fashion with guanine. However, since deoxyuridine is not a natural part of DNA, an enzyme called DNA glycosylase repairs the damage by removing deoxyuridine from the DNA strand. This leaves a gap in the strand which is rarely filled, resulting in a deleterious mutation in the genome.

Correct option is (D).