Question

Which is not correct according to Chargaff's rule?

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

Answer 1

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

A + T = C + G is not correct according to Chargaff's rule.
According to Chargaff's rule, the total amount of adenine released is equal to the total amount of thymine and similarly, the total amount of cytosine is equal to total amount of guanine, i.e A = T and C = G. Therefore, the total amount of purines is equal to the total number of pyrimidines.
Therefore,
Purines=Pyrimidines
A + G = C + T
$\frac{A+G}{C+T}=1$