Brain tissues found in exhumed Yayoi-era human skulls.
Brain tissues have been found in the skulls of three second-century people exhumed last year in Tottori Prefecture, western Japan, in what is believed to be the first discovery of its kind in Japan, researchers said Monday.
According to the prefecture's education and culture foundation and Takao Inoue, professor of anatomy at Tottori University's School of Medicine, the well-preserved brain tissues including cerebra were found in the three skulls belonging to two men and one woman.
The skulls were unearthed at the Aoya-Kamijichi Ruins in the town of Aoya in the eastern part of the prefecture last May.
Inoue said it is rare to recover brain tissues in ancient skulls as they decompose easily. Inoue and other researchers at the university are expected to take samples of nuclear DNA from the tissues to analyze human leucocyte antigen, a pattern of white blood corpuscle.
If they succeed, they will be able to clarify hereditary diseases, physique and hair characteristics of the ancient people, Inoue said, adding such findings will shed light on the origins of the people who lived in the Yayoi Period (300 B.C.-A.D. 300).
One skull believed to have belonged to a middle-aged man contains about 230 grams of brain tissue, about 20% of the total brain mass. Wrinkles on the surface of the darkened tissues are clearly visible, Inoue said, adding that minute nerve fiber structures were also confirmed by electron microscope.
Some brain tissues were found in the skull belonging to the second man. The third, which belonged to a middle-aged woman, holds about 300 grams of brain tissue, roughly 25% of her total brain.
Inoue said all three people are believed to have been killed and buried as the skull of one of the men shows signs of having been struck.
''There have been some examples of brain tissues found in previously exhumed skulls, but this is the first clear case in Japan,'' Inoue said.
Brain tissues were found in more than 260 human skulls around 7,000 to 8,000 years old exhumed in a peat bog in Florida in the 1980s.
The brain tissues in the three skulls have been preserved as the clay soil of the damp ground effectively shut out oxygen, slowing decomposition.
Inoue said the tissues are preserved at a temperature between minus 5 C and 0 C, with analysis expected to take several years.
Kazuro Hanihara, a professor emeritus at the University of Tokyo, said, ''As far as I know, it is the first time for Yayoi Era brain tissue in near-living condition to be found.'' He said the find presents a precious opportunity to conduct anatomical research directly on the brains of the ancestors of modern Japanese.
Toshinobu Fujiyoshi, an associate professor of virology at Kagoshima University, said there is only one pair of nuclear DNA in one cell and there are not many examples of extraction as they are susceptible to microbes, compared with mitochondrial DNA, which are more commonly used for DNA analysis.
''If successful, (the brain tissues) will become important evidence to find out where Yayoi people came from,'' Fujiyoshi said.
The Aoya-Kamijichi Ruins are known as ''an underground museum of the Yayoi Period'' among archeologists following the discovery there of various artifacts such as hunting tools.
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|Publication:||Japan Science Scan|
|Date:||Apr 23, 2001|
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