West Lafayette, Indiana
December 16, 2008
Think humans are complex
creatures? Consider the lowly soybean, said a
Purdue University
researcher.
When it comes to genetics, the soybean plant is far more
intricate than that of a human, said Scott Jackson, a plant
genomics and cytogenetics researcher in Purdue's Department of
Agronomy.
Jackson was among a team of researchers that mapped and
sequenced the soybean genome for a project sponsored by the U.S.
Department of Energy Joint Genome Institute (DOE JGI). The
genome was released to the public this past week and can be
viewed online at
http://www.phytozome.net/soybean.
Soybean plants have tens of thousands more genes per cell
nucleus than humans, even though the plant's complete genetic
profile is much smaller, Jackson said.
"The soybean genome is about half the size of the human genome,
but almost all of the genes in soybean are present in multiple
copies," Jackson said. "Most of the genes in humans are present
in just one copy. So while the number of genes per nucleus in
humans is between 20,000 and 25,000, with soybean it's about
66,000."
A genome is the entire deoxyribonucleic acid, or DNA, in an
organism, including genes and chromosomes. Genes carry
information for producing the proteins necessary for all
organisms. The proteins determine an organism's biological
characteristics, such as appearance, size, shape and
predisposition to disease. By knowing the genetic makeup of
soybean plants, scientists and plant breeders can develop
stronger and more productive varieties.
"With this information we can more easily target genes that are
important for, say, drought resistance, yield and seed quality,"
Jackson said. "Up to now, we would randomly mix soybean plants
to obtain the genetic traits we were looking for. In the future,
we'll be able to work with specific soybean genes. It's a much
more precise approach."
Soybean is an important crop for farmers in Indiana and the
United States. In 2007 Hoosier growers produced 210.6 million
bushels of the oilseed - fourth highest among the states - while
U.S. soybean production reached 2.59 billion bushels. Soybean is
the source of about 70 percent of the world's edible protein
and, according to the U.S. Census, more than 80 percent of the
nation's biodiesel production.
The genome project started at Purdue in 2006 and also included
researchers from DOE JGI, the University of Missouri-Columbia
and Iowa State University, with support from the U.S. Department
of Agriculture and the National Science Foundation.
Although the genomes of other living organisms, including
humans, have been mapped and sequenced, the sheer complexity of
the soybean plant made documenting its genetic composition more
difficult, Jackson said.
"Before this project we knew soybean DNA had 20 chromosomes and
a genome of about 1 billion base pairs, but we didn't know what
those 1 billion base pairs were," Jackson said. "The entire
genome has been duplicated two times. What was originally one
copy was duplicated, and then all that was duplicated again."
Purdue entomologists also have made significant contributions to
genomics research, said Sonny Ramaswamy, director of Purdue
Agricultural Research Programs and associate dean of
agriculture.
"Catherine Hill worked on sequencing the tick genome, Greg Hunt
the honeybee and former Purdue entomologist Barry Pittendrigh
the head louse," Ramaswamy said.
"The genomics research we do at Purdue is intended to enhance
food productivity and improve the lives of people."
For additional information about the Department of Energy Joint
Genome Institute, visit the DOE JGI's Web site at
http://www.jgi.doe.gov.
Writer: Steve Leer |
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