The large "O" on Skinner Butte above the University of Oregon in Eugene has been splattered with red paint on the eve of Ohio State's rematch with the No. 1 Ducks in the Rose Bowl on New Year's Day.

Today, florists sell roses in a range of colours including red, purple, yellow — and even painted with blue or multi-coloured dyes. But what colour were the first roses? A large genomic analysis ...