Erwin Chargaff's discovery regarding DNA involved ratios of which nitrogenous bases?

Erwin Chargaff's pivotal discovery centered around the ratios of nitrogenous bases in DNA, specifically highlighting that adenine (A) pairs with thymine (T) and that the amounts of these bases are equivalent in any given organism. This observation is a cornerstone of what would later become Chargaff's rules, which state that in any DNA molecule, the amount of adenine will always equal the amount of thymine, while the amount of cytosine will always equal the amount of guanine.

This relationship is fundamental to the structure of DNA because it supports the base-pairing mechanism that is critical for the double-helix model proposed by Watson and Crick. By establishing that the quantities of adenine and thymine are equal (as well as cytosine and guanine), Chargaff provided crucial evidence that helped elucidate the molecular basis of genetic inheritance and information storage within DNA. His findings underscore the specificity of base pairing which is essential for DNA replication and protein synthesis.

In terms of the other options, while they reference important relationships among the nitrogenous bases, they do not encapsulate the key principle outlined by Chargaff's rules regarding the specific pairing of adenine with thymine. Thus, the focus on adenine and thym