MEMORY is not something you would normally associate with yeast cells, but with a genetic “circuit” inside them the cells can “remember” exposure to a molecule of the sugar galactose.
A team led by Pamela Silver at Harvard Medical School in Boston created the circuit to show that biological systems could be engineered in the same way as mechanical ones. They used the galactose to trigger expression of a gene, the product of which turned on a second gene. This gene then acted to turn itself on again and again, creating an infinite loop.
So after the galactose triggers…
