Many anthropologists have assumed, based on observations of sometimes polygamous modern-day hunter-gatherers, that the basic social unit of early humans was the band or tribe rather than the family,” ScienceNOW’s Michael Balter explains as he reports on an intriguing find.

Scientists have conducted genetic testing on individuals buried in four graves in Germany. The inhabitants of two of the graves were particularly well preserved. In one, an adult male and an adult female lay on their sides, each facing a (different) young boy, with their arms intertwined. In the other grave, one adult woman was buried facing away from three children—two girls and a boy.

A team led by geneticist Wolfgang Haak of the Australian Centre for Ancient DNA extracted mitochondrial and nuclear DNA from the skeletons and determined that, in the first grave, the two adults were the parents of the two children. In the second grave, the three children were likely siblings, while the adult was not a parent. The researchers suggest she may have been an aunt or stepmother instead. However, other researchers, such as University of Sheffield archaeologist Marek Zvelebil, note that identifying relationships based on DNA may be a stretch, because the genetic markers the Haak’s used are very common in Europe.