Tassel (top photo) and ears of teosinte (Zea mays L. ssp.
parviglumis Iltis and Doebley).
(Images courtesy Hugh Iltis, University of Wisconsin.)
Picking the Perfect Ear of Cornfor More than
6,000 Years By Erin Peabody May
Those ears of sweet, crisp corn that are such a familiar part of
summertime picnics haven't always looked or tasted that way. Rather, this
staple veggieand its geneshave been tweaked over time by thousands
of generations of humans hoping to harvest a better crop.
Now, an Agricultural Research
Service geneticist and his colleagues from across the country have
discovered what impact all those years of preferential planting have had on
corn's genetic makeup.
maize having kernels of unusual color or shape.
In this week's issue of the journal
Science, the scientists report
their discoveries on which genes play a role in making corn the important food
and animal feed source we know today.
McMullen, a geneticist in ARS'
Genetics Research Unit at Columbia, Mo., worked with lead author Brandon
Gaut of the University of California, Irvine,
and scientists from the University of
Missouri and the University of
It's generally believed that corn was domesticated from its wild
relative, teosinte, some 6,000 to 9,000 years ago in Mexico. A wild grass,
teosinte doesn't look much like corn; it even lacks the "ears" that make corn
plants so recognizable.
The researchers discovered that humans, starting with ancient
Americans to present-day growers, have impacted about 2 to 4 percent of corn's
genes in their quest for a better-tasting and more cultivatable corn crop. The
scientists believe the affected genes are most likely linked to qualities like
growth and yield.
Their work has many implications, including establishing an approach
for studying the genetics of domestication of other crops and animals.
The research also indicates that while a large amount of genetic
diversity still remains for the vast majority of corn's genesenabling
future corn improvement by plant breedersknowing the 2 to 4 percent
currently lacking genetic variation will help plant geneticists use wild and
exotic corn varieties to continually improve this important crop.
This collaborative research was funded by the
National Science Foundation's
Genome Research Program.
ARS is the chief scientific research agency of the
U.S. Department of Agriculture.