The kinship matrix: inferring the kinship structure of a population from its demography

The familial structure of a population and the relatedness of its individuals are determined by its demography. There is, however, no general method to infer kinship directly from the life cycle of a structured population. Yet, this question is central to fields such as ecology, evolution and conservation, especially in contexts where there is a strong interdependence between familial structure and population dynamics. Here, we give a general formula to compute, from any matrix population model, the expected number of arbitrary kin (sisters, nieces, cousins, etc) of a focal individual ego, structured by the class of ego and of its kin. Central to our approach are classic but little-used tools known as genealogical matrices. Our method can be used to obtain both individual-based and population-wide metrics of kinship, as we illustrate. It also makes it possible to analyse the sensitivity of the kinship structure to the traits implemented in the model.

Automated summary

This paper presents a general method for computing the expected number of arbitrary kin in a structured population from any matrix population model, emphasizing the importance of kinship structure in ecology, evolution, and conservation fields. The approach utilizes genealogical matrices and can provide individual-based and population-wide metrics of kinship, as well as analyze the sensitivity of the kinship structure to model-implemented traits.