Several experiments were required to demonstrate how traits are inherited. Which scientist or team of scientists first demonstrated that cells contain some component that can be transferred to a new population of cells and permanently cause changes in the new cells?

Frederick Griffith was the first scientist who discovered that cell contains some components that can be transferred to another cell and cause a permanent change (transformation) in the new cell.

To prove this he performed an experiment in which he took two strains of Streptococcus pneumoniae which contain one rough strain and one smooth strain. Rough strain was non-virulent strain and smooth strain was virulent strain.

So he injected smooth and rough strain in mice and saw that mice die when virulent strain is injected and survive when non-virulent strain is injected. Then he injected heat killed virulent strain in which mice survived.

Then he added remain of heat killed bacteria with live smooth strain of bacteria and infected the mice and saw that the mice was killed by non-virulent smooth strain of streptococcus.

After this experiment he concluded that cells contain some component later identified as DNA which can be transferred to new population of cells and transform these new cells.