Published in Probe Volume 3(1-2): January-June 1993
Susan McCarthy, Coordinator
USDA, National Agricultural Library
Plant Genome Data & Information Center
Beltsville, MD
Genome organization is remarkably conserved between related species, reported participants at the recent Plant Genome I Conference, Nov. 9-11, 1992, in San Diego, CA. The meeting was co-sponsored by the USDA/ARS Plant Genome Research Program. Over 400 participants from around the world came together to share their research findings, with the belief that understanding genome conservation and organization should lead to faster and more efficient mapping across many species.
Conservation
Conservation was observed primarily in the low copy DNA segments, while variability, including highly repetitive sequences, were found in flanking regions. These observations were made by a number of researchers, including Jeff Bennetzen (Purdue University, West Lafayette, IN), who found that low-copy sorghum sequences conserved in maize were also largely colinear. A similar finding was made by Steve Tanksley (Cornell University, Ithaca, NY) for maize and rice; 70% of single copy DNA was conserved and whole chromosome or chromosomal arms had maintained the same gene order.
Wheat and barley are largely syntenic, that is, the linear gene order is maintained along the chromosomes. Graham Moore (Cambridge Laboratory, Norwich, U.K.) observed 60% cross- hybridization of rice and wheat markers, and that copy numbers were also conserved in the low copy number segments. See Table 1 for a summary.
Data Management
These exciting findings point to the need for data management. Tools for storing and analyzing data were discussed throughout the meeting. A mapping software workshop sponsored by Ed Coe (University of Missouri, Columbia, MO), Mary Berlyn (Yale University, New Haven, CT), and Stan Letovsky (Letovsky Associates, New Haven, CT) attracted a standing-room-only crowd of about 200 scientists. Software developments, capabilities, and needs were presented for MapMaker, GMendel, JoinMap, CProp, Hypergene, and others. Steve Knapp (GMendel: Oregon State University, Corvallis, OR)) and Steve Lincoln (MapMaker: Massachussets Institue of Technology, Cambridge, MA) have agreed to cooperate more fully in future software developments.
The Plant Genome Database, 
central
database
of the Plant Genome Research Program, was demonstrated, as were all of
the species- specific sub-databases. Dave Kristofferson
(Intelligenetics, Inc., Mountain View, CA) organized an informal
workshop to look at electronic communications for Plant
Biologists with the BioSci Newsgroups.
Map-Based Breeding
The end product of genome mapping is map-based breeding and gene
isolation. Steve Tanksley gave an elegant
demonstration of map-based breeding in tomato. The process is as
follows: wild-type tomatoes which did not exhibit desirable
phenotypic traits were bred. A high-density molecular marker map
was then used to eliminate such undesirable traits as small
fruits or poor taste quality. The end result was a tomato that
grew 15% faster and had a 15% greater yield than standard
varieties.
Marker-assisted selections are especially important for long-life-cycle species, including trees. Some markerassisted selections are now being used, in apple tree breeding, for example. A Forest Tree Genome Mapping Workshop, organized by David Neale (U.S. Forest Service, Albany, CA), was held in conjunction with the Plant Genome I conference. (See "Progress Reported at Forest Tree Genome Mapping Workshop.")