THERE'S a new "biotech" revolution under way that promises a big
payoff for farmers.
It uses modern methods of molecular biology borrowed from the
worldwide effort to chart the human genetic blueprint to map out
the simpler genetic blueprints of plants and animals. With these
methods, breeders can dramatically speed up improvement of crops
and livestock without having to use controversial and highly
regulated "genetic engineering" techniques. That's the message a
panel of agricultural scientists brought to the recent annual
meeting of the American Association for the Advancement of Science
Plant breeder Mark Sorrells of Cornell University at Ithaca,
N.Y., told a press conference that "recent advances in
biotechnology are having a fairly dramatic impact on plant
breeding." He added: "Many of these changes ... are paralleling ...
human genome research projects. They use the same techniques and
often are applied in precisely the same way."
This is an important early spinoff from the effort to map the
human genome - the set of genetic instructions that govern human
biological development from conception to birth - in which the
United States alone expects to invest several billion dollars over
the next 10 to 20 years.
Genome instructions for people, plants, and animals are encoded
in the chemical structure of long molecules of a compound called
deoxyribonucleic acid or DNA. Coherent segments of DNA that control
different aspects of biological development are called genes. The
DNA molecules carrying the genes are grouped together in bodies
called chromosomes. These chromosomes carry the genetic heritage
that parent organisms pass to their offspring generation after
What the genome explorers are trying to do is map the precise
location of various genes on the chromosomes. They want to tag the
genes with distinctive markers the way a "dig safe" crew tags
underground cables with distinctive little flags.
The tags are DNA sections that do not themselves take part in
gene action. They may be small repetitive sequences called
microsatellites or other structures that biochemical probes can
Gene-tagging technology is developing fast to meet the needs of
human genome mapping. That is a long-term project. The practical
payoff today lies in the fact that the technology already is at a
stage where rapid progress is being made in mapping crop plant and
livestock genomes. This is what is beginning to revolutionize plant
and animal breeding. …