But how did the snapdragon cousins create accented patterns that appeared to be equally effective in the same environment?
To find out how color differences in these snapdragons arose, scientists compared the genomes of the subspecies in a study published Thursday in Science.
They found that the magenta-yellow plants and their yellow-magenta mirrors shared most of the plant’s 30,000-some genes — but not a handful related to color. Those genes behaved like artists painting billboards with different techniques and palettes.
And nature appeared to respond to the colorful expressions of these genes. Bees favored a couple of patterns and neglected plants with other color schemes, the researchers believe, selecting for certain genetic combinations.
The key difference between the two most prevalent subspecies lie in how the snapdragon developed a yellow accent on a magenta flower.
To do this, it used something genetic researchers call small RNA — small because, in a structure shaped like a hairpin, it only holds a little bit of information that regulates a gene’s ability to express itself. (Generally speaking, RNA may hold a couple thousand units, whereas small RNA might hold no more than two dozen).
These proteins act something like a stencil, ensuring that the flower sprays yellow onto only a small portion of the lower lip. Without that genetic stencil, yellow would go everywhere.
The snapdragon with the opposite color scheme used something else for its magenta accent, just as many other plants and animals do for their color variations, said Enrico Coen, a biologist at the John Innes Centre in Britain who led the study.
Dr. Coen and his colleagues were surprised that one subspecies had this small RNA stencil and the other one didn’t. They’d seen small RNA turn off genes in plenty of other organisms, but in this case, “it was being used in nature to create differences that you could see,” he said.
Genetics are intricate, but the lesson here is simple. Whether creating a magenta arrow for a yellow flower, or vice versa — these subspecies both do the job well.
“Rather than always thinking what’s the best, what’s the best — maybe there are cases in which there are two equally good solutions,” said Dr. Coen.
After all, if there were only one way to live, there’d only be one organism out there.