This came from their observation that the 3' terminal sequences of 18S rRNA from Drosophila melanogaster, Saccharomyces cerevisiae, and rabbit cells are identical: GAUCAUUA -3'OH.
Isto deduciuse da observación de que as secuencias 3'-terminais do ARNr de 18S da mosca Drosophila melanogaster, o lévedo Saccharomyces cerevisiae e os reticulocitos de coello son idénticas: GAUCAUUA -3'OH.