Diagram of sorghum BAC SB40L16. The insert of sorghum BAC 40L16 is indicated along with a ruler with the size in kb on top. The red arrows indicate kafirin genes, green arrows other genes, and blue arrows DNA transposons. A key is inserted to indicate the putative function of genes in this BAC clone. The kafirin gene cluster is highlighted by a box. The bars below the gene cluster represent different size of fragments containing the kafirin genes, those released by different restriction enzymes such as HindIII, BamHI and SpeI, respectively. These three enzymes were used for genomic or pulsed-field gel electrophoresis and Southern-blot analysis.