sequentially related to bounds sequence of The genomic exons of a transcript bound the sequence of the genomic introns of the same transcript (but the introns are not subsequences of the exons) x bounds the sequence of y iff the upstream-most part of x is upstream of or coincident with the upstream-most part of y, and the downstream-most part of x is downstream of or coincident with the downstream-most part of y is bound by sequence of Christopher J. Mungall