Question

What are Chargaff's rules?

Short answer

Chargaff's rules state that in DNA, adenine equals thymine and guanine equals cytosine; and that the proportion of these bases varies between species but is constant within the same species.

Step-by-step solution

Explanation of the First Rule

Chargaff's first rule, also known as the parity rule, states that in deoxyribonucleic acid (DNA), the amount of adenine (A) is equal to the amount of thymine (T), and the amount of guanine (G) is equal to the amount of cytosine (C). This can be expressed as \(A = T\) and \(G = C\).

Explanation of the Second Rule

Chargaff's second rule specifies that the relative quantities of adenine, thymine, cytosine, and guanine bases vary from species to species, but are constant within members of the same species.