Were related children sought out specifically?

The mechanism for this is less clear.

The genetic relatedness of 25 percent of the assemblage might reflect a practice in which families contributed multiple children to the ritual.

It might reflect the drawing of ritual participants from a specific social stratum in which the relevant families were closely connected by kinship.

It might reflect the specific population structure of communities from which participants were drawn, where high degrees of relatedness within small communities meant that randomly selected individuals would frequently share genetic connections.

The diet similarity among relatives adds another dimension.