Question

Who discovered that genes are made up of DNA?
A. Sutton
B. Avery, MacLeod and McCarty
C. Watson and Crick
D. Benzer

Answer 1

Hint: Oswald Avery, Colin MacLeod and Maclyn McCarty have shown that DNA is capable of transforming cell properties, clarifying the chemical existence of genes. Avery began research into pneumococcal bacterial transformation to improve pneumonia therapies.

Complete Answer:
The Avery–MacLeod–McCarty experiment was an experimental demonstration on DNA. They tried to prove DNA is the substance that causes bacterial transformation. DNA was defined by Avery, MacLeod and McCarty as the "transforming theory" while researching Streptococcus pneumonia, a bacteria that can cause pneumonia.

- The bacteriologists were interested in the difference between two strains of Streptococci described in 1923 by Frederick Griffith. But Avery and McCarty noted that proteases-enzymes that degrade proteins-did not undermine the concept of transformation. They prepared cultures that had the heat-killed S strain.
- Later they removed lipids and carbohydrates from the solution. They then treated the solutions with various digestive enzymes to kill the target compound. Finally, they introduced living R strain cells to the culture. They wanted to see which cultures would develop and get transformed into S strain bacteria.
- Only the S strain bacteria did not grow in the culture treated with DNase. There was no change because there's no DNA. This suggested that DNA was the genetic variable transmitted between cells.
- The chromosomal theory of inheritance is suggested by Sutton along with Boveri.
Watson and Crick have suggested the double-helical DNA structure.
Benzer has suggested a gene model and how they influence an organism's behaviour.

So, the correct option is 'Avery, MacLeod and McCarty'.

Note: Oswald Avery and colleagues built on Frederick Griffith's results to prove the genetic material is DNA.