New method of analyzing ancient DNA has found chromosomal abnormalities in four of them. Scientists from the Max Planck Institute for Evolutionary Anthropology (MPG, Germany) found seven cases of trisomy among the 9,855 samples they analyzed.

The four remains are between 2,800 and 2,400 years old. One, the most recent, was buried in a Christian cemetery in Helsinki (Finland), in the 17th century. The two oldest are from a site in Bulgaria, where they found a six-month-old girl, dated to about 4,900 years ago.