Biology / Unit 6 Bio 1195 short lesson, about 20 seconds
Avery, MacLeod, and McCarty (1944)
Captions available
The idea
Oswald Avery, Colin MacLeod, and Maclyn McCarty identified DNA in 1944 as Griffith's transforming principle by destroying each candidate molecule in turn.
In practice
Destroying the sample's proteins and RNA left transformation intact; destroying its DNA with a DNA-digesting enzyme stopped transformation completely.
Where people slip
This 1944 result faced skepticism for years — Hershey and Chase's independent confirmation is what settled the question.
Your place on the trail
Every lesson rests on earlier ones and opens later ones. Tap any to jump.
Something wrong in this lesson? Flag it · Sources for Biology