The principle describes a fundamental relationship within the structure of DNA: in any sample of 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 parity is observed across diverse species and signifies a crucial element of DNA’s double helical structure. As an illustration, if a DNA molecule contains 20% adenine, it will also contain 20% thymine, leaving 30% for guanine and 30% for cytosine.
This observation played a pivotal role in deciphering the structure of DNA. Its importance lies in demonstrating the complementary base pairing within the DNA molecule, providing a critical piece of evidence for Watson and Crick’s model. The consistent A=T and G=C ratios strongly suggested a pairing mechanism, with adenine specifically binding to thymine and guanine specifically binding to cytosine. This precise pairing ensures the stability and accurate replication of genetic information.
