South Carolina scientists trawl for DNA as new lab searches for answers on illnesses that affect shrimp

They've long provided sustenance both monetary and culinary for Charleston.

Now they're feeding scientists' curiosity, too.

While shrimp and grits are served up along Meeting Street, scientists down the road are peering into the crustacean's DNA at the new high-tech Hollings Marine Lab on James Island.

They are sequencing the shrimp genome and using DNA data to study what makes shrimp sick.

Yes, sequencing the shrimp genome. Just like with people.

It turns out the complex science that made headlines in 2000, when geneticists announced they had mapped all human DNA, could have consequences for your dinner plate.

Supporters of the shrimp genome project say it could one day mean more plentiful fresh, local shrimp for U.S. shoppers -- who now buy 87 percent of the shrimp they eat from foreign sellers.

The newest marine lab in the country, Hollings opened last year and is one of the largest institutes focused on marine genomics nationwide, said Paul Gross, a Medical University of S.C. assistant professor who works there.

And it's growing.

The National Oceanic and Atmospheric Administration announced last month that it would dedicate another $575,000 to the S.C. shrimp disease project this year, bringing the total amount it's given to $2.1 million.

"It's not like no one else has done anything on shrimp disease," said Craig Browdy, a senior marine scientist with S.C. Department of Natural Resources. "But we're doing some of, I think, the leading edge of it."

For shrimp and people, genetics promises a shortcut to understanding why disease affects different organisms differently, scientists say.

It could show why some people resist disease better, for instance. And it may one day explain whether environmental factors such as pollution play a role in who gets sick when.

That kind of knowledge would be valuable to shrimpers who trawl in the ocean, as well as those who grow shrimp in farms, scientists say.

While researchers have studied disease in farm animals such as cows, pigs and chickens for decades, they've largely overlooked marine animals, Gross said.

"We're playing catch-up," he said. "But it's a new industry."

Along Hollings' sterile hallways, robotic arms do sensitive DNA work while scientists in other rooms study molecules, whole animals and everything in between.

Aquariums of coral line counters in one lab. Down the hallway, round tanks that will eventually hold fish wait to be filled.

It's a base for researchers from the Medical University of South Carolina, the College of Charleston, the state DNR, NOAA and the federal National Institute of Standards and Technology.

The concentration of resources stands in contrast with the void researchers found in 1997, when an outbreak of so-called white spot disease struck South Carolina.

When white spot infects a pond of shrimp, it often kills 90 percent of them or more, Gross said.

"If a wheat farmer lost 90 percent of their field, they'd be out of business," he said. "White spot is a real big problem."

The disease cost Southeast Asian shrimp growers $6 billion annually over four years during outbreaks there (the disease doesn't harm people who eat infected shrimp).

At the time, South Carolina had a small shrimp farming industry that harvested about $3 million in shrimp a year, said Robert Chapman, associate research scientist with DNR.

"After the outbreak, it was virtually wiped out," Chapman said.

S.C. scientists tested shrimp in the ocean and in aquaculture ponds for white spot, and were surprised at what they found.

"Turned out the thing is everywhere," Chapman said. "Been here for millennia, probably. At least 10 years."

So why did some shrimp manage to stay healthy when others got sick?

"What became clear when this occurred was we didn't know very much about how shrimp resisted diseases," Gross said.

Chapman and his colleagues wanted to fill in the gaps. Genetics provided the fastest path.

"We decided to do for the shrimp what the human genome project has done for the humans," Chapman said.

Because genetic research is so expensive, the scientists at Hollings are not trying to map every shrimp gene.

Instead, they are focusing on so-called expressed genes, which are an organism's active genes. They've isolated about 3,000 since starting five years ago, Gross said, with a goal of identifying 10,000 to 15,000.

After isolating genes, they look at which are turned on and off in response to disease or environmental stressors such as pollution.

They hope to eventually find a genetic "marker" that signals whether a shrimp has disease-resistant genes. Breeders could then sell batches of those shrimp to growers who would raise them to maturity and sell them again.

The lab's genomic research is already being used by the private sector, Chapman said.

"This is being sucked up as fast as we can produce it," he said.

There are others looking at marine genetics here and abroad. Gross heads up an international consortium of scientists. But few U.S. researchers are focusing specifically on shrimp genes.

Tufts University associate professor Acacia Alcivar-Warren is one of them.

She said she has struggled to find money for her own research.

"My wet lab is the size of a closet," she said. She called the S.C. shrimp disease research "a very good project."

Eventually, the research could provide hope for a lagging industry.

About $1.8 million worth of shrimp was harvested in South Carolina aquaculture farms in 2002, said Ray Rhodes, a state resource economist.

Al Stokes, manager of the Waddell Mariculture Center in Bluffton, S.C., said the state has six major growers. Texas has the country's largest shrimp farming industry, he said. But South Carolina's temperate climate means it could grow shrimp 150 days a year, he said,

Both farmers and fishermen who catch wild shrimp are under increasing pressure from imports.

In the year 2000, the wholesale value of shrimp harvested and landed in S.C. was $15.5 million. In 2003, the same amount of shrimp was harvested, but the value had sunk to $8.5 million, Rhodes said.

Gross said it makes sense for the government to support research that helps aquaculture, the way agricultural science benefits farms.

"We don't hunt for our cows anymore," he said. "There is in fact really no reason to hunt for shrimp."

The shrimp genome project has also led Hollings researchers to begin genetic research into other marine animals, including coral, oysters and dolphin.

"Shrimp are only the beginning," Chapman said.

Scientists may one day turn regularly to the sea for new drugs. And shrimp could end up teaching scientists something about themselves. Fruit fly gene research led to an important discovery about immune response genes in humans, for instance, Gross said.

"No learning is wasted," he said.

• Wholesale price of shrimp harvested and landed in South Carolina in 2000: about $4 per pound

• Wholesale price of shrimp harvested and landed in South Carolina in 2003: $2.20 per pound

SOURCE: Ray Rhodes, resource economist with the S.C. Department of Natural Resources
Heather Vogell: (803)327-8509; hvogell@charlotteobserver.com