New Delhi, June 30 -- Today, for about $29, you can buy a petunia that glows in the dark. The Firefly Petunia, sold by synthetic biology company Light Bio, was created using genes from luminous mushrooms and emits a soft green light from its buds.

After receiving approval from the US Department of Agriculture, it became the first bioluminescent plant to be sold to the public. Even though the condition of sale specifies that it is for personal use only, a petunia can grow from a cutting placed in a glass of water-which means that beyond the terms of the contract, there is nothing to keep this engineered organism from proliferating.

The Firefly Petunia was created by a process increasingly referred to as programmable biology, a phrase ins...