efnasamband

Efnasamband is a term used in Icelandic and other Nordic languages to denote kinship or familial relationship between individuals or groups. It refers to connections through shared ancestry, and can cover both blood relationships (consanguinity) and, in some contexts, ties by marriage (affinity). The concept describes how closely people are related and is often expressed in degrees or as a measure of relatedness.

In anthropology, demography and sociology, efnasamband helps explain family structures, lineage, inheritance patterns, and marriage practices. Legal systems in many countries regulate rights and duties based on levels of kinship, such as prohibitions on certain marriages or the distribution of inherited property, using established degrees of consanguinity. In population genetics and genealogy, efnasamband underpins methods for reconstructing pedigrees and estimating how closely individuals are related.

Measuring efnasamband involves both historical records and biological data. Pedigree analysis uses generations of documented relationships to calculate degrees of relatedness, while genetic methods assess relatedness directly from DNA, often using concepts like identity by descent or coefficients of relatedness. These approaches can be combined to infer familial connections, especially when records are incomplete.

Sources of information on efnasamband include genealogical records, civil and church registries, census data, and modern DNA testing. Limitations arise from missing or inaccurate records, privacy considerations, and cultural variations in what is regarded as a valid familial connection. See also kinship, genealogy, and consanguinity.