Researchers are using genetic engineering to make purple limes.

Purple limes could be the future of the Sunshine State's citrus crop, say researchers from the University of Florida. 
They're doing it via genetic engineering.
According to a press release, "These modified Mexican limes have a protein that induces anthocyanin biosynthesis, the process that creates the 'red' in red wine, and causes the limes to develop a range of colors in the pulp from dark purple to fuchsia." 
One of the researchers, Manjul Dutt, noted, "Anthocyanins are beneficial bioflavonoids that have numerous roles in human well-being. Numerous