MOUNT VERNON, Va., — The DNA collected from 13 trees at Mount Vernon, planted under George Washington's supervision, will be profiled and cataloged as the first step in the creation of a genetic database for specific ornamental trees.
While the human genome has been detailed in a worldwide effort by thousands of scientists, nothing similar has been done with trees, noted J. Dean Norton, director of horticulture at Mount Vernon. Norton has enlisted the aid of Virginia Tech and the USDA Forest Service's National Forest Genetic Electrophoresis Laboratory in Placerville, Calif., to use the Washington Trees as the beginnings of in-depth research into the genetics of a number of important tree species.
"This will be the start of a genetic database of these trees," said Norton. "George Washington was always experimenting, trying new ways of growing his crops. I think it's great that this 18th century site can still take the lead in research."
The 13 Washington Trees, the only trees now living that are known to have been planted at Washington's direction, are seven American Holly, one Canadian Hemlock, two Tulip Poplar, two White Ash, and one White Mulberry. Samples collected from 17 other trees of the same species at Mount Vernon and the surrounding area will also be evaluated in the project.
Norton contacted M.A. Saghai Maroof, a plant geneticist at Virginia Tech and an expert in the analysis of the DNA of plants, to help with the project.
"The genetic structure of plants are similar, but there are unique challenges in working with different types of plants," said Saghai Maroof. "My expertise is in discovering genes that provide disease resistance in agricultural crops. For this project, it was important to bring in a laboratory with the capacity and the expertise to deal with DNA of trees."
Saghai Maroof contacted the Forest Service laboratory.
Valerie Hipkins, director of the National Forest Genetic Electrophoresis Laboratory, said she was excited to be involved in the Washington Trees project.
"This facility provides molecular genetic information for the evaluation and protection of the genetic resource represented by our nation's trees," she said. "We will be doing DNA 'profiling,' which will be similar to the type of work most people are familiar with in criminal cases, or paternity cases, and the like. With people there is a tremendous database of information, so we are able to match DNA to an individual with a great degree of accuracy. There is no similar database for trees. This to a very great extent is new; we'll be breaking new ground."
The first scheduled collection of cutting by horticulturists from Mount Vernon is set for Feb. 18 while the trees are in a dormant stage. Additional cuttings will be collected in the late spring or summer when the deciduous trees are in leaf. The cuttings will be express-shipped to the Forest Service laboratory in California, where scientists will immediately begin the process of extracting DNA for detailed analysis.
According to Hipkins, each sample’s genetic markers will be generated at multiple locations along the string of genetic information thought to show variation within a species. This information can be used to identify a sample as coming from a particular individual. The lab will produce a bar-code like pattern for each individual using fingerprinting techniques based on polymerase chain reaction, or PCR, techniques. The laboratory procedures will take weeks to conduct. Hipkins expects to be able to provide a report on the lab's findings by the end of the summer.
Those findings will be important to Norton not just because of their intrinsic scientific value. Being able to identify individual trees – especially the Washington Trees – solves another problem for him.
Those 13 historically important trees are nearing the ends of their normal expected life spans. Last summer, cuttings were taken for rooting, and buds gathered for grafting from the trees to produce genetically identical clones. Once those duplicates are established, Mount Vernon will be able to plant them on the Estate, preserving them for future use on the grounds and for other horticultural endeavors.
The genetic profiles determined by the Forest Service's laboratory will be used to authenticate clones of these historically important individual trees, ensuring they will be recognized and protected in the future, Norton said.
He acknowledges that the eventual establishment of a database of genetic information may have a broader significance in the conservation of trees in the future. In this, the Washington trees will play an important role.
"What better trees to serve as the foundation of this database," he asked. "This type of genetic research is the path to the future. Who better to lead the way than the Father of Our Country, George Washington?"
Fact Sheet
Genetic testing of George Washington's Trees
WHO:
J. Dean Norton is director of horticulture for Mount Vernon. Phone: 703-799-8661, e-mail: dnorton@mountvernon.org.
Dr. M.A. Saghai Maroof, professor of crop and soil environmental sciences at Virginia Tech, is scientific consultant to Mount Vernon for the testing project. Phone: 540-231-9791, e-mail: smaroof@vt.edu.
Dr. Valerie Hipkins, director of the USDA Forest Service's National Forest Genetic Electrophoresis Laboratory, Placerville, Calif., will conduct laboratory testing. Phone: 530-622-1609, e-mail: vhipkins@fs.fed.us.
MEDIA CONTACTS:
Virginia Tech: Stewart MacInnis,540-231-5863, macinnis@vt.edu
Mount Vernon: Stephanie Brown, 703-799-8605, sbrown@mountvernon.org
WHAT:
Tissue samples from 13 trees, the only trees that are known to have been planted at Mount Vernon under the supervision of George Washington, will be examined and their genetic profiles determined. In addition, tissue will also be examined from 17 trees that are unrelated to the Washington Trees. The samples from these trees are needed to begin assessing the amount of variation among individuals within a given species. The Washington Trees are seven American Holly, one Canadian Hemlock, two Tulip Poplar, two White Ash, and one White Mulberry. The non-Washington Trees will be of the same species, for a total of 30 trees to be tested.
WHY:
In August of 2001 material was collected from these 13 trees, which are nearing the end of their normal life expectancy, and genetic duplicates are being produced through propagation and grafting. Once these duplicates are established, Mount Vernon will be able to plant them on the estate, preserving them for future use on the grounds and for future horticultural programs.
The genetic profiles to be determined by the Forest Service's laboratory will be used to authenticate clones of these historically important individual trees, ensuring that the only living witnesses to the life and times of George Washington will be recognized and protected for future generations.
In keeping with the spirit of scientific innovation exhibited by George Washington, the genetic information of these relatively unstudied species will be available to scientists worldwide, and will serve as a base of information for the collection of additional genetic data concerning these species. The collection of information from all 30 trees is considered a first step toward more in-depth studies of the species in the future, including the development of databases containing the genetic information that will be available to scientists worldwide.
WHEN:
Collection of small samples from the 13 trees will begin Feb. 18, 2002, during the trees' dormant stage. Additional samples will be collected in the spring when the deciduous trees are in leaf. Laboratory analyses will begin within days of the collection of samples. A final report of the findings is expected by September 2002.
WHERE:
Collection of samples will take place on the grounds of Mount Vernon. Analyses will be conducted at the USDA Forest Service's National Forest Genetic Electrophoresis Laboratory, Placerville, Calif.
HOW:
All living organisms contain DNA, and the DNA in all organisms has the same functions and structure. The use of DNA for identification is called "DNA profiling," and has on occasion been referred to as "DNA fingerprinting." The technologies and statistical principles used to determine an individual's DNA profile is also the same among all living organisms. For people, DNA evidence is routinely used in identifying missing persons, suspects is criminal cases, or for other purposes. DNA profiling is also performed in plants. Just as every human individual has unique DNA, with the exception of identical twins, every plant individual has unique DNA, with the exception of clones. DNA profiling in plants is important in distinguishing varieties, cultivars, and species of horticultural or ornamental species. Less common is the attempt at distinguishing individuals within a plant species.
In this beginning phase of laboratory work, scientists will focus on understanding the nature and extent of genetic variation in these species. DNA will be extracted from branches collected from the trees at Mount Vernon, and using polymerase chain reaction, or PCR, "fingerprinting" methods a bar-code like pattern will be generated for each individual. Future work will entail creating databases for each species. This will enable us to determine the probability that two individuals share a profile by chance, and therefore, lead us to the ability to authenticate the George Washington trees into the future.
Research contact: J. Dean Norton, director of horticulture, Mount Vernon 703-799-8661, e-mail: dnorton@mountvernon.org.