In 1953 Watson and Crick proposed that rarely formed isomers of DNA bases cause spontaneous mutations to occur during the copying of DNA. Such mutations would be easily accommodated because tautomeric mispairs do not distort the helical DNA structure. The disfavored-tautomer model for spontaneous mutation formation (mutagenesis) was rapidly adopted by biologists and included in textbooks, despite the absence of supporting experimental evidence. In 2018 Kimsey, Al-Hashimi and colleagues showed that Watson's and Crick's prediction was correct.
Digital text from PubMedCentral at this link.

Order of authorship in the original publication: Kimsey, Szymanski....Al-Hashimi.

(Thanks to Juan Weiss for this reference and its interpretation.)