Sequence Comparison of the Starch Branching enzyme1 Gene Among Several Native American Varieties of Maize.

Previously, we determined that the allele for starch branching enzyme 1 (sbe1) in a high amylose line, GEMS-0067, would translate into a protein with six amino acid polymorphisms relative to an allele in a lower amylose line, H99ae. A review of the published sbe1 sequence data indicates that four of the amino acid polymorphisms appear to be unique to GEMS-0067, and two are found in grass relatives of maize, but not in other maize varieties that have thus far been characterized. Interestingly, the maize alleles of sbe1 are remarkably uniform, i.e., nearly all have the same amino acid usage as found in H99ae. Most of these maize varieties are inbreds or hybrids and we are curious if the uniformity might have resulted from selection or fixation due to a genetic bottleneck. We are presenting sequence data for sbe1 from a more diverse sample including several teosintes.