The isotope findings added another dimension to the picture of relatedness among the 64 children.

Related children — those identified as close relatives through genomic analysis — also tended to show similar stable isotope profiles, suggesting that they consumed similar diets during their lives.

This is not surprising, because children raised in the same household by the same parents would typically eat from the same food sources and drink from the same water supplies.

The dietary similarity among relatives is consistent with the genetic relatedness findings and adds a separate line of evidence suggesting that these children came from the same social and household environments.

The specific dietary patterns revealed by the isotope data — what foods were consumed, what proportion of the diet came from marine versus terrestrial sources, what specific signature the local water and food sources left in the bones — provide information about the social backgrounds of the children.