Figure 2.

Diagrammatic outline of the gene-island sequencing protocol. A maize (Zm) BAC is sheared and subcloned into a standard cloning vector. Zm subclones arrayed on filters are hybridized with an orthologous, radiolabeled sorghum (Sb) BAC. Only low-copy regions conserved between the Sb and Zm BACs will hybridize. Positive Zm clones are identified and sequenced. Contigs are assembled and analyzed. Black areas along hypothetical BACs indicate conserved open reading frames. Colored areas flanking open reading frames represent non-transcribed regions.