SALT LAKE CITY—Sixty-one years ago, Northwest Airlines Flight 4422 smashed into Alaska’s Mount Sanford, killing all 24 passengers -- merchant marines returning to the U.S. from China -- and six crew members aboard.

The wreck of the DC-4 was presumed to have been buried in snow and swallowed into a glacier. For nearly 50 years, no debris or remains were found.

Then, in 1997, two airline pilots -- Kevin McGregor and Marc Millican -- who had been taking annual trips to the mountain since 1994 to find the wreck, found airplane fragments. In 1999, they found a mummified arm.

Yesterday, at the annual meeting of the American Chemical Society here, Colleen Fitzpatrick of genealogy consulting firm Identifinders, of Huntington Beach, Calif., described the nine-year effort that led to matching the remains—a single arm and hand—to Francis Van Zandt, born in 1911 in Bennington, Vt.

Soon after the arm was found, Fitzpatrick joined a long, painstaking effort to identify the remains, involving forensics, detective work, and a bit of luck of the Irish. Researchers were able to tease out fingerprints that had virtually disappeared, Fitzpatrick said, and to extract DNA from mitochondria -- the powerhouses of the cell -- in the tissue, which in the meantime had been embalmed (Scientists typically use either mitochondrial DNA or Y chromosome DNA, in men, to trace lineage; a cell has hundreds of copies of mitochondrial DNA compared with just one copy of the Y.) Tests on that DNA ruled out a match with 28 of the victims.

To match the DNA to Van Zandt’s, Fitzpatrick had to find a living relative in the same maternal line, since mitochondrial DNA is almost always inherited from the mother alone. But that was easier said than done. Van Zandt did have living relatives in the U.S., but none of them were matrilineal.

Fitzpatrick learned from Van Zandt’s brother’s birth certificate that his mother, Margaret Conway, was an Irish immigrant born in Timerick, Ireland, in 1876. Fitzpatrick figured that the actual place must have been Limerick, which had been misspelled. After trying unsuccessfully to find records for a Margaret Conway in Limerick County, Fitzpatrick had another guess: Conway might have lied about her age.

Sure enough, she found records for a Margaret Conway born in 1871 to John Conway and Ellen Drum. Fitzpatrick then located a possible living Irish relative named Maurice Conway. He showed her a family tombstone, which bore the names of Margaret’s parents.

Despite Fitzpatrick's detective work, at this point the odds of getting a mitochondrial DNA match were still very small, because of the need for matrilineal descent. But Fitzpatrick had an lucky break. Thanks to intermarriage, Maurice Conway’s mother also happened to be a descendent of Ellen Drum’s sister, along four generations of mother-to-daughter inheritance.

When Fitzpatrick had Maurice Conway's DNA checked last year, the search was over: The arm found in Alaska was Van Zandt’s.

Fitzpatrick said that the experience can help identify the bodies of fallen soldiers from past wars. “The reason we do this,” she said, “is to make sure that there is no more Unknown Soldier.”

Top photo: Kevin McGregor and Marc Millican in Alaska in 1998 at the crash site. Bottom photo: The DC4 that crashed in Alaska in 1948. Both courtesy Kevin McGregor.