Fig. 4: Cloning by complementation.
A cdc2ts mutant is able to grow at the restrictive temperature when cells carry the human CDC2 gene on a plasmid. This gene is able to complement the yeast cdc2ts mutant function and cells can grow and divide to form colonies (white arrow heads). Cells that lose the plasmid are no longer able to divide, but continue to grow and form elongated cells (black arrow heads)
