Write Erwin Chargaff’s observation with respect to DNA molecule structure.

Chargaff’s observation with respect to DNA molecule structure is as follows:

(i) Chargaff analysed the DNA of different species, determining its composition of A(Adenine), T(thymine), C(cytosine)and G (guanine) bases.

(ii) A,T,C and G were not found in equal quantities.

(iii) The amount of bases varied among species, but not between individuals of same species.

(iv) The amount of A always equalled the amount of T, and the amount of C always equalled the amount of G (i.e A=T, C=G).