Question

Evolution is experimentally demonstrated by

• A. Rapid mutation- Neolamarckism
• B. Survival of the fittest- Wallace
• C. Replica plating- Lederberg
• D. Ancon sheep- Neo Darwinism

Answer 1

The correct option is C Replica plating- Lederberg

Evolution is experimentally demonstrated by replica plating by Lederberg. Joshua Lederberg and Esther Lederberg performed replica plating experiment to know the genetic basis of adaptations. With the help of this experiment, they demonstrated genetic basis of adaptations in bacteria. A dilute solution of bacterial cells was inoculated on a semi-solid agar plate. Many distinct bacterial colonies developed on the agar plate. Each colony was arisen due to repeated cell division by a separate bacterium. The plate which was having colonies was used as ‘master plate’ to obtain its replicas. These experiments clearly showed that the pre-existing gene mutation was the genetic basis of adaptation. The penicillin-sensitive and penicillin-resisting colonies were same in all replica plates. It means that the original ‘master plate’ was containing penicillin-resistant colonies of mutant bacteria before their exposure to the antibiotic.