Mammoth DNA Unlikely to Yield Clone

N E W   Y O R K, March 13, 2001 -- Sit in ice for 20,000 years, and the water damage, ultraviolet radiation and chemical decay will likely shatter your DNA to bits.

That makes dreams of cloning a mammoth pulled out of a chunk of Siberian ice last fall unlikely, but even in pieces, the DNA will still tell scientists much about the extinct pachyderm.

“There is a lot we can do with even bad DNA,” says Alex Greenwood, a research fellow at the American Museum of Natural History’s mammology department in New York City. Greenwood was one of the researchers who presented their views about the mammoth during a panel discussion at the museum last week.

A Sudden Disappearance

The genetic code, Greenwood said, could enable scientists to draw more detailed relationships within the elephant family tree, which is known to have originated in north Africa. It could also help identify the gender of skeletons already studied.

Greenwood is particularly interested in what the frozen DNA might shed on why mammoths disappeared suddenly between 10,000 and 11,000 years ago. Until recently, most scientists believed the thawing of the last Ice Age, which occurred around the same time, was the killer.

Human Culprits?

Two other theories are also viable contenders: humans hunted mammoths into oblivion or the mammoths died of disease. Greenwood focuses his attention on the latter possibility, noting that Asian elephants carry a strain of herpes lethal to African elephants. He hypothesizes a plague struck the mammoths thousands of years ago. It is even possible that humans inadvertently introduced the virus or germs as they spread into the mammoths’ habitat.

If disease played a role, Greenwood hopes genetic material from the virus or bacteria is also preserved in the frozen carcass in Siberia.

While he is anxiously looking forward to what the mammoth DNA can tell him, Greenwood all but dismisses the idea of a Jurassic Park-style cloning.

He is not alone. Most scientists agree it is premature to talk of cloning the woolly mammoth. The overall condition of the animal is unknown, even though some fur and flesh was spotted after a small patch of ice was melted with a hair dryer.

One scientist involved estimates it will take at least a year just to defrost the carcass, which is still sitting inside a 23-ton piece of ice. Piecing the animal’s DNA together will take much longer.

Unknown Contents

Mammoth remains, in the forms of bones, tusks and teeth, are relatively plentiful, found in much of the northern Hemisphere, the elephant’s former habitat. However, DNA is scant or absent in most skeletal remains.

When the frozen mammoth was pulled out last year, expedition leaders suggested the presence of soft tissue would make it possible to clone the extinct animal.

Although cloning is no longer science fiction since the world was introduced to Dolly the sheep, the process is still difficult.

Scientists created Dolly by removing the genetic material out of an egg cell, replacing it with the nucleus of a cell from the original Dolly, and implanting the egg in a surrogate mother sheep.

The ‘Humpty Dumpty’ Problem

Breathing life into the extinct woolly mammoth is an different, possibly impossible operation. During life, the damage to fragile DNA is repaired naturally. After death, the genetic code quickly breaks down.

Robert DeSalle, a curator at the American Museum of Natural History, calls this the “Humpty Dumpty” problem. These genetic fragments would likely be 10,000 to 100,000 times smaller than the DNA pieces the researchers in the human genome project are working with, DeSalle said.

Except for a simple flu virus, “No organisms have been manipulated this way,” according to DeSalle.

Then there are the ethical issues, even if a cloned herd could survive in places like Canada or the Dakotas. “In principle,” Greenwood argues, “they don’t belong here anymore.”

What is a mammoth?

Mammoths were part of the elephant family, sharing from a common ancestor with Asian and African elephants — the only two species that exist today — that lived about 4 million years ago.

There were about 20 species of mammoths, of which the woolly mammoth is just one.

Habitat: Mammoth remains are found in most parts of the northern Hemisphere, where they once thrived. Frozen remains have been found in Siberia and Alaska.

When: Mammoths thrived from about 4 million years ago until about 10,000 years ago, when they went extinct.