In which year did a trio of scientists, Avery, MacLeod and McCarty, prove that except viruses, all living organisms have DNA as their genetic material?
Show answer & explanation
Correct answer: C
Explanation
The correct answer is option 3 i.e. 1944.
In 1944, scientists Oswald Avery, Colin MacLeod, and Maclyn McCarty made a groundbreaking discovery that proved DNA is the genetic material in living organisms, except viruses. Their work was based on experiments conducted with Streptococcus pneumoniae bacteria, specifically examining the process of transformation.
Previously, scientists debated whether proteins or DNA was the carrier of genetic information. Avery, MacLeod, and McCarty demonstrated that when they extracted DNA from a virulent strain of bacteria and introduced it into a non-virulent strain, the non-virulent bacteria transformed into virulent ones. The transformation could be stopped by destroying the DNA, but not by destroying proteins, showing that DNA, not proteins, was the material responsible for genetic inheritance.
This discovery laid the foundation for modern genetics and molecular biology, providing critical evidence that DNA carries genetic information in all living organisms, except for certain viruses, which use RNA instead.