The sap-sucking insects manage this unexpected feat thanks to ancestors that incorporated genes from a fungus into their own DNA more than 100 million years ago, says Nancy Moran of the University of Arizona in Tucson. Both pea aphids and peach aphids carry genes that make nutrients called carotenoids, she and Arizona colleague Tyler Jarvik report in the April 30 Science.
“To my knowledge, this is the first report of an animal that can synthesize its own carotenoids,” says evolutionary biologist Takema Fukatsu of the National Institute of Advanced Industrial Science and Technology in Tsukuba, Japan.
Carotenoids, a brightly colored group of molecules including beta-carotene and lycopene, are powerful antioxidants and immune-system boosters. Carotenoid pigments can put the reds and yellows into feathers and other show-off tissues for courting displays, and they catch light in the human retina. Yet in essence, “there’s only one way to make carotenoids in all of nature,” Moran says, and animals apparently lost the basic toolkit long ago in their evolutionary history.
Many microorganisms, fungi and plants still have the power, however. Carotenoids put the blush in tomatoes, and the fiery range of yellows, reds and oranges into flowers. Read more