Tower mutant colony of baker's yeast

Photograph of a tower mutant colony (white) of Saccharomyces cerevisiae or Baker's yeast growing on an agar plate surrounded by normal colonies (red). In the tower mutant colony, yeast cells grow upwards forming a projection or protusion. It is not known whether the cause of this is due to a random genetic mutation or other underlying growth mechanisms. Saccharomyces cerevisiae is a species of yeast commonly used in baking, brewing and wine making.