At first, the grains of rice that ingo potrykus sifted through his fingers did not seem at all special, but that was because they were still encased in their dark, crinkly husks. Once those drab coverings were stripped away and the interiors polished to a glossy sheen, Potrykus and his colleagues would be-hold the seeds' golden secret. At their core, these grains were not pearly white, as ordinary rice is, but a very pale yellow-courtesy of beta-carotene, the nutrient that serves as a building block for vitamin A.
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