二、突变产生的机理 (b) standard and anomalous base Standard base- pairing arrangements pairing arrangements occur if bases are in the rare tautomeric forms. Base Th mine (common formy Adenine(common form) mispairings due to tautomeric shifts were originally thought to be a major H一N source of errors in replication, but Cytosine(common form) Guanine(common form) such structures have not been Anomalous base pairing arrangements detected in dna and most evidence 一H·非市NA now suggests that other types of anomalous pairings are responsible 看非音看H for replication errors A Thymine(common form Guanine (rare form) Genetics Ch12.11Genetics Ch12.11 二、突变产生的机理 • (b) Standard and anomalous base￾pairing arrangements occur if bases are in the rare tautomeric forms. Base mispairings due to tautomeric shifts were originally thought to be a major source of errors in replication, but such structures have not been detected in DNA, and most evidence now suggests that other types of anomalous pairings are responsible for replication errors