Figure 3.

Schematic alignment of maize SPS and SPS-like genes. The gene number indicates the SPS gene family. Protein-coding exons within genomic sequences are shown in black with those regions derived only from maize cDNA (EST) sequences shown in dark gray. The 5′- and 3′-UTRs are shown in light gray. Gaps in the maize exon sequence are indicated by dashed lines, and gaps in the introns are indicated by two angled lines with the minimum size of the intron indicated above. Black triangles indicate the positions of the translation start (ATG) and stop (TAA, TGA) codons. The white triangles mark the positions where introns are absent from one gene in relation to the others, and the asterisk shows the position of an intron in the maize ZmSPS1 gene that is absent in the orthologous rice gene (OsSPS11).