Neolithic farmers grew modified maize | FARMERS in the Stone Age were
altering the genetic makeup of their foods more than 5000 years ago, say
plant geneticists in Minnesota.

By comparing 13 strains of maize and 17 strains of its wild ancestor
teosinte, John Doebley and his colleagues at the University of Minnesota in
St Paul propose that Neolithic Central Americans turned grass into corn by
selecting a gene for branch size (Nature, vol 398, p 236).

The team suggests that farmers altered the control region of a gene called
tb1 by always re-sowing teosinte crops with the biggest seeds. As a result,
tb1 is much more active in maize than in the grass, causing the branches to
grow fat ears of corn rather than thin tassels of seed.

From New Scientist, 20 March 1999