(genetics) a segment of DNA that is involved in producing a polypeptide chain; it can include regions preceding and following the coding DNA as well as introns between the exons; it is considered a unit of heredity; "genes were formerly called factors"
moving from one place to another and back again; "he traveled back and forth between Los Angeles and New York"; "the treetops whipped to and fro in a frightening manner"; "the old man just sat on the porch and rocked back and forth all day"
appearing or developing early; "precocious flowers appear before the leaves as in some species of magnolias"
characterized by or characteristic of exceptionally early development or maturity (especially in mental aptitude); "a precocious child"; "a precocious achievement"