What relationship between base concentrations was noted by Chargaff?

Chargaff's rules state that in the DNA of any given organism, the amount of adenine is equal to the amount of thymine, and the amount of guanine is equal to the amount of cytosine. This relationship reflects the base-pairing rules, where adenine pairs with thymine and guanine pairs with cytosine through hydrogen bonding. These findings contributed significantly to the understanding of DNA structure, particularly in elucidating how the bases pair in a double helix formation, as proposed by Watson and Crick. The equality of these base concentrations is fundamental in maintaining the integrity and stability of the DNA molecule during replication and transcription processes. This observation further laid the groundwork for the establishment of molecular biology as a discipline by elucidating the underlying principles of genetic coding and heredity.