Cloning of the y1 Locus of Maize, a Gene Involved in the Biosynthesis of Carotenoids.

The y1 gene is one of the genes responsible for the production of [beta]-carotene in the endosperm and leaves of maize. We have cloned a Robertson's Mutator-tagged allele of the y1 gene (y1-mum) by using a Mu3 element as a hybridization probe. We substantiate that the cloned sequence is a portion of the y1 gene by molecular analyses of a revertant of a putative Mutator-induced y1 allele and the incidence of insertions within the cloned y1 sequence from several independently derived Mutator-induced y1 mutant stocks. The y1-mum sequence was used to isolate the standard Y1 allele, which conditions the presence of [beta]-carotene in the endosperm of the maize kernel.