Researchers Find DNA in Ancient Bacteria

Aug 16, 11:19 AM

Current Headlines: By NEWSDAY

By melting segments of some of the world's oldest Antarctic glaciers, researchers at Rutgers University discovered that bacteria within the ice had identifiable DNA.

Even more shocking, the 8-million-year-old bacteria still had the ability to grow.

Kay Bidle, the study's lead author and an assistant professor of marine and coastal science at Rutgers, said modern bacterium contains about 300 million DNA base pairs. The 8-million-year-old bacteria had only 210 base pairs left.

"We were surprised that DNA that was so small and degraded was able to grow," he said.

Previously, the oldest ice examined for microorganisms was about 300,000 years old, Bidle said. This new research clues scientists in to just how long DNA can live.

"If DNA reaches a point where it's completely degraded," Bidle said, "that's going to represent a time period past which your genes and DNA will not be sufficient to support life."

Janet Hearing, a research assistant professor of molecular genetics and microbiology at Stony Brook University on Long Island who did not take part in the study, said the findings echoed recent research that discovered a variety of previously unidentified bacterial species in oceans. But, she said, while scientists knew there was unidentified DNA on Earth, no researchers had been able to manipulate such aged bacteria.

"They did something that many people, including myself, are absolutely amazed they could do," Hearing said, "which is to get viable cells to grow again."

Although the bacteria are ancient, they have connections to cells present on Earth today and are not dangerous to humans, said Paul Falkowski, another author of the study and a Board of Governors professor in Marine and Geological Sciences at Rutgers.

"They don't look like lions and tigers," he said. "They're just little round things or little rods."

But, Falkowski said, the bacteria could cause changes in marine ecosystems if the ice melted and they were released into the ocean and allowed to replicate.

One of the primary ways in which bacteria evolve, Bidle said, is when they latch on to free-floating DNA. As climate change causes the Antarctic glaciers to melt and the bacteria within them is poured into the ocean, natural changes likely will occur in the marine ecosystem.

Bidle said the research also disproves what had long been one of science's theories about the origins of life on this planet: that a comet from another solar system brought bacteria to Earth.

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