apparently makes assumptions of this type when he in- 
terprets the knob situation in teosinte from western 
Guatemala. Here the four shortest chromosomes are sup- 
posedly controlled by the maize gradient, the six largest 
ones by the teosinte gradient, and the condition is re- 
garded as one step in the evolution of teosinte to maize. 
But all assumptions of this kind lead finally to the same 
impasse: recombinations resulting from segregation and 
crossing-over and involving the knobs of one species and 
the gradient-controlling genes of the other are inevitable. 
Hybridization of the two species is certain to be followed 
by general shifts in knob positions. Until such a phenom- 
enon has been shown to occur, the basic tenet of Long- 
ley’s hypothesis, that maize has stemmed directly from 
teosinte, will continue to remain inadequate in accounting 
for the established facts; as it has for more than fifty 
years since it was first proposed by Ascherson. 
ANTHROPOLOGICAL IMPLICATIONS 
There is no doubt that western Guatemala is a concen- 
trated center of diversity of maize. In so far as diversity 
is associated with centers of origin and, in the absence of 
conflicting evidence, this region must also be regarded as 
a center if not the center of origin for cultivated maize 
varieties. 
If the older hypotheses which have maize deriving 
directly from teosinte are accepted, the implications are 
clear. In that case the region comprising the Department 
of Huehuetenango and perhaps the adjoining Depart- 
ments of El Quiche, Totonicapan, Quezaltenango and 
San Marcos (as well as the adjoining State of Chiapas in 
Mexico) is the primary and probably the only center of 
domestication of maize. Presumably it is also the center 
where maize agriculture originated and from which it 
spread to all those parts of the New World where it was 
[ 243 | 
