In late 1984 the archaeologists discovered that brain tissue had survived in many of the skulls. Lumps of greasy, brownish material was found in several skulls when they were opened for examination. Suspecting that this was brain tissue, the researchers sent the intact skulls for X-ray, CAT scans and magnetic resonance imaging (MRI), which showed recognizable brain structures. In addition, cell structures were seen under a microscope. At least 90 of the recovered bodies had brain tissue that survived, due to the preservative effects of the peat. The state of preservation of the brain tissues allowed a determination that the bodies were buried in the peat within 24 to 48 hours after death. This preservation allowed researchers to sequence DNA from the brains. The DNA indicated Asian origin, similar to that of the four other major haplotypes of Native American peoples, and a relatively rare haplogroup, X. The DNA also indicated that one family had used this grave site for over a century.