Putting DNA to Work
  IMPROVING CROPS

From Teosinte to Corn

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Ancient Teosinte

Corn's ancestor did not have large ears. Instead, hard, nut-like kernels were distributed in small, feathery cobs over many tertiary branches.

Modern Corn (Maize)

Corn today comes in many varieties, all of which have ears that contain many soft kernels.

From Teosinte to Corn

The genes that control a number of specific traits have been identified.

For example, a gene on chromosome #1 causes the ears of corn to be big and to grow on a few short branches. In contrast, the ears of teosinte are scattered over many small branches.

A gene on the second chromosome causes more rows of kernels to grow, yielding more food per corn plant.

A gene on the fourth chromosome causes corn kernels to have small, soft casings. Teosinte kernels have much larger, harder kernel casings that make them hard to eat.

Photos of teosinte ears and corn ears

Ancient Teosinte (left) Corn's ancestor did not have large ears. Instead, hard, nut-like kernels were distributed in small, feathery cobs over many tertiary branches.

Modern Corn (Maize) (right) Corn today comes in many varieties, all of which have ears that contain many soft kernels.

Photos courtesy of John Doebley.


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