Researchers in Japan thrilled the country's anthropologists last week with the news that they have found human brain tissue in three 1800-year-old skulls. This rarely preserved soft tissue could yield genetic information about early Japanese populations.
The three skulls were among 5000 bones from at least 92 people recovered last year from the Aoya-Kamijichi site in Tottori Prefecture, on the Japan Sea coast. Takao Inoue, an anatomist at Tottori University in Yonago, was spooning mud out of one of the skulls when he found white tissue with the consistency of tofu. "I was really surprised," he says. He speculates that cold temperatures and the heavy, moist clay in which the bodies were buried preserved the tissue. The skulls are thought to be from two men and a woman of the Yayoi period, from about 300 B.C. to A.D. 300, which produced pottery well known to art historians. The largest brain fragment weighs about 300 grams--a good-sized chunk, considering a full brain weighs about 1400 grams.
The discovery has Japan's anthropological community buzzing. Finding such old, well-preserved soft tissue is a first for Japan, says Keiichi Omoto of St. Andrew's University in Osaka. Although bone fragments hold less useful mitochondrial DNA, the tissue could yield DNA from the cell nucleus, including genes on the Y chromosome and in the human leukocyte antigen complex which are used to track populations. By comparing genes in the preserved tissue to those carried by living people, researchers may be able to "shed light on the origins of the Yayoi," Omoto says. There could also be signs of genetic diseases that may have afflicted the Yayoi, Inoue adds.
Those who want to see the brains for themselves will find them on display at the Tottori Prefectural Museum.