As home gardeners in the U.S. page through seed catalogs and pick out their favorite heirlooms, there's a new seed that has never been available to them before: a tomato the color of a concord grape with plum-colored flesh. It looks otherworldly, maybe Photoshopped. But it's not.

This nightshade is purple because its creators at Norfolk Plant Sciences worked for about 20 years to hack color genes from a snapdragon flower into the plant. The genes not only provide pigment, but high levels of anthocyanin, a health-promoting compound.

This dusky fruit, named the Purple Tomato, is the first genetically modified food crop to be directly marketed to home gardeners – the seeds went on sale Saturday. Last year, a handful of small farmers started growing and selling the tomatoes, but until now, genetically modified foods were generally only available to commercial producers in the U.S.