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Hold still, mummy, this won’t hurt a bit

Scientists pull an ancient tooth for DNA, clues

By Carolyn Y. Johnson
Globe Staff / October 18, 2009

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It was the oddest of scenes: A neurosurgeon delicately threaded a scope up the neck and into the skull of a disembodied, 4,000-year-old mummified head. Sweating with concentration, another doctor clamped a molar and began to rock it gently back and forth.

Three hours later, the nerve-wracking operation yielded a tooth, a time capsule holding precious DNA, which might reveal the identity of the ancient Egyptian head.

The surgical team - doctors from Massachusetts General Hospital and curators and conservation specialists from the Museum of Fine Arts - was assembled recently in an attempt to solve this longstanding ancient art mystery.

The question arose after the 1915 excavation of a tomb in a necropolis 186 miles south of Cairo. Robbers had disturbed the tomb, which belonged to Governor and Lady Djehutynakht, who ruled the district of Hermopolis in about 2000 BC. They left behind a torso, scattered mummy wrappings, fine examples of Egyptian art, objects for the afterlife, and the head.

In preparation for an exhibit opening at the museum today, the head was subjected to a full modern medical workup, including sophisticated imaging at a lab in Charlestown, various failed attempts at genetic test ing, and finally, the delicate dental procedure last month.

“We’re trying to get every piece of information we can out of the material from the tomb,’’ said Rita E. Freed, chairwoman of the museum’s Department of Art of the Ancient World. “The 19th century was the era of unwrapping mummies. . . . Then, X-ray technology became available and we could X-ray mummies. . . . And then, people began to realize you could really do pathology.’’

The mummy’s ancient DNA, the scientists knew, might reveal its gender, and perhaps more, if any of it had survived. They began to take samples, unsuccessfully trying to get DNA from a small patch of skin from the neck of the mummy and a finger that had been recovered from the tomb. Finally, they settled on the place where the genetic material was most likely to be intact - deep in the pulp of a tooth.

“All of us were extremely concerned about not disturbing the head, because this is really a one-of-a-kind artifact,’’ said Dr. Paul H. Chapman, a Mass. General neurosurgeon who helped recruit colleagues to take on the mummified head as a patient, and has long been fascinated by ancient Egypt.

“When you do an operation and you do it often enough, you know the steps involved and you know if you do them it will succeed,’’ Chapman said. The mummy surgery was far different.

Because of the fragility of the head, yanking the tooth out was not an option. The doctors went in through the open end of the neck. They inserted a scope with a camera attached to see what they were doing inside the head. If they accidentally bumped the side of the head, it let loose a flurry of dust, Chapman said.

The first tooth they tried wouldn’t budge. The second slowly gave way to methodical wiggling that ensured that it - and the head - stayed in one piece. An art conservator held the head in her arms for the entire procedure to ensure no harm would come to it.

“It was somewhat tense,’’ said Dr. Rajiv Gupta, a neuroradiologist at Mass. General who was also part of the operating team. “The person is long dead,’’ so no life hangs in the balance. “But in a way, what you’re doing - this is as precious as an artifact can be, from 4,000 years ago. We were being as careful as possible.’’

The team is still awaiting the results of the tooth analysis, but what the scientific scrutiny has revealed so far has surprised both doctors and curators.

High-tech scans of the head in 2005 showed that the ancient Egyptians used sophisticated surgical techniques on the dead, to remove bones in the jaw and cheek area without disturbing the skin.

That finding led Chapman and Gupta to speculate that the ancient Egyptians might have done the unusual surgery to prepare mummies for the “Opening the Mouth Ceremony,’’ a mortuary ritual in which use of the mouth to eat, drink, and breathe was restored for the afterlife. The ceremony has been thought to be symbolic, involving priests touching objects to the mouth, but the physicians think the surgery might be a part of it, since it is aimed at freeing the jaw.

Not everyone agrees.

“We have no evidence they actually ever physically wrenched the mummy’s mouth apart or did anything else,’’ said James P. Allen, a professor of Egyptology at Brown University. “It’s all spiritual, not physical at all, so why this jaw was removed, who knows.’’

Dr. Miguel A. Sanchez, an associate professor of pathology at Mount Sinai School of Medicine, said he also disagrees with the interpretation because in the warm climate, rigor mortis would be short, and would not keep the jaw shut. Still, he said, the doctors at Mass. General “did a terrific job; the data is very sophisticated. . . . The dynamics of using new technology to understand what we call paleopathology is fascinating, because you have to be open to all kinds of interpretations.’’

The next step is to analyze the DNA. Dr. Fabio Nunes, a neurologist at Mass. General who normally works on brain tumors and cancer genetics, drove the tooth down to the medical examiner’s office in New York, deeming it too precious for the mail. The team chose to have the tooth analyzed there because the office has expertise in working with degraded DNA.

“The problem with the ancient DNA is, because it’s so degraded and in such small amounts, we really don’t know how much DNA we’re going to have,’’ Nunes said. He hopes to learn the gender of the mummy, and perhaps to find out about its ancestry.

Freed acknowledged that in analyzing something so ancient, it is difficult to be certain about any interpretation, but said the insights from modern medicine have been illuminating. The insights also go the other way, inspiring doctors on the cutting edge of medicine. “It was eye-opening to me,’’ Gupta said. “I was, number one, totally astounded by the fact these people were able to do what they were able to do at the time.’’

Carolyn Y. Johnson can be reached at cjohnson@globe.com.