Note on Estimates of the Inbreeding Coefficient through Study of Pedigrees and Isonymous Marriages

Document Type

Brief Communication

Authors

P H. Cabello, Instituto Oswaldo Cruz
H Krieger, Instituto Oswaldo Cruz

Abstract

Crow and Mange (1965) developed a method to estimate the inbreeding coefficient (F) through an ingenious surname analysis. Such formulations assume a regularity of transmission of surnames, monophyletism, and random occurrence of consanguineous marriages. Accordingly, the ratio of isonymous partners to F of the offspring is equal to 4. Nevertheless, genealogy analyses show that the consanguineous marriages do not necessarily occur regularly. Therefore the isonymy analysis gives a misestimation of the inbreeding coefficient, depending on the prevailing form of nonrandomness. We suggest a small correction to the formulation in situations when pedigree information is available. The weighted mean of the ratio of isonymous partners to F of the known consanguineous marriages is suggested as a way to improve the formulas. The technique was applied to a northeastern Brazilian sample, and the results agree well with those o f bioassays and therefore provide an apparently more realistic estimate of the inbreeding coefficient by isonymy.

Recommended Citation

Cabello, P H. and Krieger, H (1991) "Note on Estimates of the Inbreeding Coefficient through Study of Pedigrees and Isonymous Marriages," Human Biology: Vol. 63: Iss. 5, Article 13.
Available at: https://digitalcommons.wayne.edu/humbiol/vol63/iss5/13