For nearly a decade, David Denlinger has studied an insect smaller than his pinkie nail that lives thousands of miles away in one of the world's most inaccessible areas. The Ohio State University entomologist and his colleagues have made six trips to the Antarctic Peninsula since 2004, weathering 20-foot waves and weeks away from home to study the Antarctic midge.

For nearly a decade, David Denlinger has studied an insect smaller than his pinkie nail that lives thousands of miles away in one of the world�s most inaccessible areas.

The Ohio State University entomologist and his colleagues have made six trips to the Antarctic Peninsula since 2004, weathering 20-foot waves and weeks away from home to study the Antarctic midge.

This particular insect caught Denlinger�s interest, he said, because of its ability to survive severe dehydration, the absence of oxygen and being submersed in salt water. How hardy is this bug? The midge spends 22 months of its 24-month life encased in ice before thawing out and coming back to life just long enough to reproduce.

The time in Antarctica and his OSU lab has shown Denlinger and colleagues what this bug can do. Now the team is starting to figure out how the midge is able to do it.

The key, Denlinger said, might be its remarkably small genome � the smallest that has been found in an insect to date.

�It has really stripped down its genome to the bare essence,� said Denlinger, senior author of new research published in the journal Nature Communications.

At 7 millimeters long, the Antarctic midge is the largest land animal that lives year-round on the Antarctic Peninsula. (Antarctic penguins and seals mostly come on to land to breed, Denlinger said.)

The midge�s genome consists of 99?million base pairs of nucleotides � 6?million base pairs fewer than the next-smallest known genome.

It�s so small that the team that sequenced the midge initially thought it had made a mistake. � We thought we blew it and missed something big,� Denlinger said.

He and colleague Richard Lee of Miami University found that the Antarctic midge has approximately 13,000 genes � not surprising given its size. What was astounding, Lee said, is just how little �junk� DNA the midge carries. Simply put, this insect is lean and efficient.

�What we have here is an animal that�s really living at the extreme of life,� Lee said.

The scientists are interested in the midge�s dehydration response, how it depresses its metabolism during the winter and how it deals with other stresses caused by its harsh climate, Denlinger said.

They�re also interested in the genes that enable the midge to tell time, he said.

Lee said that the midge can shut off about 25 percent of its genes when it enters a dormant state, such as when it is encased in ice and dehydrated for months. That means it turns them on when it�s time to wake and mate.

�By having the genome and knowing the sequence, we can actually go in and take a look at those genes and correlated proteins that are being turned on and off� as the midge is exposed to different stresses, he said.

The midge can tolerate losing as much as 75 percent of its water, Denlinger said.

Then, �You pour a little water on them, they plump up and go on their merry way,� he said.

The research could one day lead to figuring out how to freeze and later thaw human organs for transplantation, Denlinger said.

The National Science Foundation has funded the research in Antarctica since December 2004 and will continue to do so again beginning next winter, when researchers will take the first of three more trips to Palmer Station in Antarctica.

The National Science Foundation manages the U.S. Antarctic program, funding projects and providing logistical support for research there, said Peter West, manager of outreach and education.

The foundation�s goal is to �build a knowledge base for other researchers in the field,� he said.

Denlinger said his research team has received more than $2.2 million from the National Science Foundation for its six trips to Antarctica.

The trip to Palmer Station, one of three U.S. stations in Antarctica, takes about a week, Denlinger said. Much of that time is spent on an icebreaker from southern Chile to the U.S. station by way of the Drake Passage.

�We�re usually pretty (sea)sick by the time we get there,� he said. �It�s a pretty rough trip."

Palmer Station can accommodate about 45 people, Denlinger said, including about 15 scientists.

Denlinger and an OSU colleague have also been awarded $437,622, according to foundation documents, for future Antarctic research. �We�re anxious to know if some of the other genomes of other Antarctic organisms are like this,� he said.

jryan@dispatch.com

@Jimryan015