BY CAROLYN Y. JOHNSON > Boston Globe

It’s a plant more commonly associated with lava lamps and Pink Floyd than cutting-edge science. But Thursday, a small Marblehead, Mass., company plans to post online the hundreds of millions of letters of DNA that make up Cannabis sativa in a first step toward truly understanding and enhancing marijuana’s therapeutic potential.

For years, Kevin McKernan built genome sequencing technologies – powerful tools designed to provide insights into cancer and potential treatments.

But when desperate friends with cancer forwarded studies of medical marijuana’s use, he became intrigued. Earlier this summer, he founded Medicinal Genomics, a small firm that will partner with pharmaceutical companies to explore compounds made by the plant.