Kinship and social class
American Presidential ancestries
Figures 1a and 1b are the bicomponents of American Presidental ancestors, 1at ignoring generation and focusing on cohesion, where there is a cohesive core and a distant periphery, and 1b looking at 34 temporal levels running back to European ancestries. Together these made a 3-dimensional core-periphery image. Images 1c and 1d show a slight surplus of male over female links in the core of these networks but this is due to memory bias for patrinyms earlier on and matrinyms in more recent times. This would imply that both core and periphery are bilaterally composed, i.e., a matter of social class rather than intermarriages among patriline families.
Contrast with a conical clan structure
Comparable graphs for a Turkish nomad clan show conical cohesion and no discrete core-periphery structure