and would be expected to have a low survival value. 
Why, then, should this allele have even a higher fre- 
quency than the 7'w allele? 
All of these difficulties can be avoided and the problem 
becomes quite simple if we assume instead that wild corn 
was 7'uT'u which gave rise through mutations to the 
lower alleles, tu’ and tu. The 7'u gene has largely dis- 
appeared; the tu’ gene is in the process of disappearing ; 
and it would seem that eventually all of the world’s corn 
will be tutu, the most efficient genotype from the stand- 
point of usefulness to man. 
Another assumption mentioned earlier, which is al- 
most equally simple and plausible, is that wild corn was 
half tunicate, tu’tw", which, through mutation, gave rise 
to the nontunicate genotype, tutu, and, through unequal 
crossing over, to the strongly tunicate form 7'u7'u. The 
first might have been preserved because of its obvious 
usefulness, the second because of its supposed magical 
properties. 
It should be noted that both of the above assumptions 
postulate that the progenitor of cultivated corn was a 
form of pod corn and that changes at the 7'w-tu locus 
have been involved in corn’s evolution under domesti- 
cation. 
RECONSTRUCTING THE ANCESTOR OF CORN 
Perhaps the strongest support for the pod-corn theory 
is provided by a genetic reconstruction of the ancestral 
form (15). This was accomplished by crossing pod corn 
with a number of freely-tillering varieties of popcorn and 
through selection combining the 7’ gene with a com- 
plex of minus modifying factors and a majoring inhibit- 
ing factor. The plants so produced have several stalks; 
the tassels bear both male and female flowers, the former 
above and the latter below on the same branches; the 
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