New York Times, November 3, 1999
MORE THAN ONE WAY TO ALTER A PLANT
The recent debate about the genetic engineering of crops raises the question, How does it differ from traditional methods of breeding specialty crops? Here is a look at the two processes and their advantages and limitations.

Traditional Plant Breeding

For centuries, when farmers wanted to introduce a new trait to their favorite crops (making them more durable, productive or marketable) they would breed the crop with a plant of the same or similar species possessing the desired characteristic.

HOW IT IS DONE
In trying to get a pear with the coloration of an apple, for example, agricultural engineers might crossbreed their preferred pear with a chosen variety of apple. This would produce a range of hybrids with combinations of the characteristics of both fruits. Of those, the fruit closest to the desired result would be chosen and bred again with the apple. This process would be repeated over many generations until the desired trait was achieved.

LIMITATIONS
Only traits from species that are relatively close to one another can be combined. The process can take months to years to produce the desired results.

GENETIC ENGINEERING
Advances in a number of fields have allowed agricultural scientists to take genetic material responsible for a desired trait — from any plant, animal, insect, bacterium or virus — and introduce it to a given crop.


HOW IT IS DONE
There are two common methods for introducing the genetic material:

1: The first uses Agrobacterium, a bacterium that naturally alters a plant's DNA. Researchers place the desired genes into the bacterium, then infect the plant. The bacterium inserts the new genetic codes into the plant's DNA. The cells are then grown to maturity, producing future generations with the desired characteristic.

PRIMARY CROPS
Wide-leafed plants like tobacco, tomato, apple and pear.

2: The second method uses a "gene gun" to propel genetic material coating thousands of microscopic shards of tungsten into a group of plant cells. The tungsten penetrates the cells and carries the DNA to the area of the nucleus. The DNA makes its way to the nucleus and joins with the genes inside.

PRIMARY CROPS
Narrow-leafed plants like grasses and grains.

LIMITATIONS
Traits can be bred more accurately, but some complex traits remain difficult if not impossible. Also, there is some risk of achieving unexpected results.