There are two arguments to the theory about the domestication of
maize. One theory is from Mangelsdorf and Reeves stating that
the teosinte could not be the ancestor of maize. This was
because the differences between maize and teosinte are so great
that it would have taken thousands of years to evolve. So, they
argue that it had evolved in nature over a great length of time.
The second theory is argued by Beadle. He challenged Mangelsdorf
and Reeves stating that even the slightest change in a gene can
cause a significant difference in the plant. In the experiment
involving tga1, it was confirmed that the simple mutations in
genes can cause a major change in the plant's phenotype. The
change in this gene could result in the soft casing of the
maize, or could be the hard casing of the teosinte. Thus, this
paper proves the second theory, that the teosinte can be the
ancestor of the maize. The tga1 gene is expressed in the ear,
but not elsewhere in the maize. So it will not affect any other
part of the plant. Thi