Experiments with bacteria in the 1930s showed that exposing

Experiments with bacteria in the 1930s showed that exposing a nonvirulent (noninfectious) strain of bacteria to a heat-killed virulent strain can convert the nonvirulent strain into a virulent o What might explain this phenomenon? As you have just read, humans and other mammals have a large amount of intergenic DNA. It requires much energy to maintain C \"extra\" DNA; therefore, scientists reason it must have a function. Explain.

Solution

1. Non-virulent strain is converted to virulent strain through transformation. It allows for horizontal transfer of gene.

2. Extra-DNA functions as house-keeping gene. Their functions are yet to be ascertained.