Is 'gene stacking' the next big thing?

Scholars' startup could build superior plants; idea gets publicity today

Greg Copenhaver has heard stories about professors who stumble across a discovery, invest countless hours in the lab and eventually strike it rich.

The associate professor at UNC-Chapel Hill is fully acquainted with the first two steps. The part about the big payoff could depend on a new technology described today in the online journal Genetics, published by the Public Library of Science.

Known as gene stacking, the technology could fundamentally change the way plants are bred while saving seed companies millions of dollars.

In theory, it allows crop scientists to custom-design plants that have traits such as the ability to withstand drought, resist insects and fend off rot -- all at the same time.

The company behind the claim is Chromatin, which Copenhaver co-founded with University of Chicago professor Daphne Preuss. Chromatin signed its first contract in May with agricultural giant Monsanto. It expects to eventually have agreements with every major seed producer in the U.S.

The attraction is not just the ability to alter plants: Scientists have been doing that for thousands of years. The promise is the ability to alter the genetic traits of crops with a degree of accuracy never before possible.

If it works outside the lab, it could replace the current approach of growing hundreds of lines of the the same crop -- each one slightly different from the others -- and hunting for just the right mix of traits.

"Their technology is very promising for the future," said David Fischoff, who oversees technology strategy for Monsanto.

Even those who have no involvement in the project say its advantages would be obvious. "It's absolutely helpful," said David Bird, a professor of plant pathology at N.C. State University. "It's the kind of technology that many companies are going to be interested in."

Beating the odds

Copenhaver talks with confidence about Chromatin's potential, but the company is not a sure bet. It has, however, beat the odds thus far.

Its roots can be traced to a plant mutation that Preuss discovered in 1994 while working in the lab. The plant, arabidopsis, is so common that Copenhaver describes it as the "fruit fly of plant research."

But the mutation Preuss analyzed 13 years ago was different: It exhibited some of the same characteristics as yeast cells. Yeast is a favorite among geneticists, because it is relatively easy to manipulate its genetic code -- its DNA.

Preuss had studied yeast cells before, so she understood her good fortune right away.

Two years later, Copenhaver was a post-doctoral student working with Preuss. Together they set about manipulating the genetic structure of this common research plant.

'Stacking' the cells

It is a painstaking, time-consuming process that happens at a level unseen by the naked eye.

Imagine a single cell. Inside that cell is a nucleus. Inside the nucleus is a chromosome -- a linear, thread-like strand of DNA. On the chromosome is a gene.

It is at this level of detail that Preuss and Copenhaver work. In corn, a gene on a strand of DNA determines whether the corn can resist drought or disease.

Change the genes on a chromosome and you change the way the corn looks and grows. Add multiple genes to that plant -- gene stacking -- and the corn is changed in many ways.

"Conventional plant breeding is hitting its limits," Copenhaver said. "Breeders have bred everything they know how to breed without putting new genes in."

The two researchers knew this when they started working together in 1996, but it took four years for them to co-found Chromatin. By 2001, Copenhaver was not even living in Chicago: He had landed a faculty job at UNC-CH.