Silkworms make silk. That much you knew. But did you know that these industrious little caterpillars can spin silk of different colors: white, yellow, pink, even green. Silkworms get the pigments they use to color their gossamer product from mulberry leaves, the only food they eat. They then use the silk to make themselves some seriously comfy cocoons.
Some mutant silkworms can only make white cocoons. These monochromatic characters have a mutation in a gene called Y…which stands for Yellow Blood. They don’t absorb the yellow-colored carotenoids from mulberry leaves, so their blood is colorless and their cocoons are white. This week, scientists from Japan announce that the Y gene produces a protein that grabs onto carotenoids. This protein allows cells in the gut to extract the yellow pigment from mulberry leaves…and cells in the silk gland to take it up from the blood.
By providing mutant silkworms with a good copy of the Y gene, the scientists were able to restore their ability to make yellow cocoons. Such genetic manipulations might someday allow researchers to engineer silkworms that make custom-colored silk. And with a little extra tweaking, maybe they could get the worms to monogram your silk PJ’s as well.