Which statement reflects Chargaff's Rule regarding nucleotide ratios?

Chargaff's Rule states that in a given double-stranded DNA molecule, 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 translates into the relationships A = T and G = C, leading to the conclusion that the A:T and G:C ratios are indeed close to 1 in properly complementary DNA structures.

This equality underlies the base pairing mechanism during DNA replication and contributes crucially to the stability and structure of the double helix. When analyzing the composition of DNA, it becomes evident that deviations from these ratios typically indicate either modifications in the DNA structure or the presence of different types of DNA (such as in various organisms or species).

Given this understanding, the assertion that A:T and G:C ratios are always equal or close to 1 accurately captures the essence of Chargaff's findings and is why this choice is the correct answer. The other options do not align with the established biochemical principles that Chargaff's work elucidated.