Class 12 NEET Biology Biotechnology and Its Applications

(b) : Rice produces carotene in the leaves but the biosynthetic pathway is turned off during plant development in grains. Transgenic rice, Golden Rice, was engineered by inserting two genes that restart the carotenoid biosynthetic pathway leading to the production and accumulation of carotene in the grains. These are the naturally occurring down-regulated genes. But the transgenic variety does not show down regulation and grains are rich in vitamin A.