Although biological relationships are a universal reality for all human beings, the concepts of “family” and “family bond” depend on both the geographic region and the historical moment to which they refer. However, the concept of “family” can be determinant in a large variety of societies, since it can influence the lines of succession, inheritances and social relationships, as well as where and with whom an individual is buried. The relation between a deceased person and other members of a community, other individuals of the same necropolis, or even with those who are buried in the same tomb can be analysed from the genetic point of view, considering different perspectives: archaeological, historical, and forensic. In the present work, the concepts of “family” and “kinship” are discussed, explaining the relevance of genetic analysis, such as nuclear and lineage markers, and their contribution to genealogical research, for example in the heritage of surnames and Y-chromosome, as well as those cases where some discrepancies with historical record are detected, such as cases of adoption. Finally, we explain how genetic genealogical analyses can help to solve some cold cases, through the analysis of biologically related relatives.

Background: This study relies on the discovery of two pit burials (LTA and LTB) of the Bronze Age Cogotas I archaeological culture (circa 3600–2950 BP) in Spain. LTA was a single burial and LTB contained three skeletal remains of two adults and a newborn or foetus at term. Aim: The central question posed by this find was whether the LTB tomb constituted a traditional nuclear family (father, mother and son or daughter). Methods: Ancient and forensic DNA protocols were employed to obtain reliable results. Autosomal, X-STR markers and mitochondrial DNA were amplified. Subsequently, different kinship probabilities were estimated by means of LR values calculated using the Familias 3 software. Furthermore, an allelic dropout sensitivity test was developed in order to evaluate the influence of allelic dropout phenomena on the results. Results: It was possible to determine the molecular sex of all individuals and to establish a maternal relationship between the perinatal individual and one of the adults. Conclusion: The remains in the LTB tomb were not a traditional nuclear family (father, mother and son/daughter) and it was probably a tomb where two women, one of them pregnant, were buried.