Question

Which is not correct according to Chargaff's rule?

• A. $\frac{A+G}{T+C}=1$
• B. $A+T=C+G$
• C. $A+G=C+T$
• D. Purines = Pyrimidines

Answer 1

The correct option is B $A+T=C+G$

Chargaff performed chemical analysis of DNA.

According to Chargaff's rule, the total amount of adenine (A) is equal to the total amount of thymine (T) and similarly, the total amount of cytosine (C) is equal to the total amount of guanine (G),
hence, A = T and C = G.

So, the total amount of purines is equal to the total amount of pyrimidines.
Therefore, Purines = Pyrimidines
A + G = C + T
$\frac{A+G}{T+C}=1$.