title: Isolation factors and kinship by isonymy in a group of parishes in northern Tuscany (Italy): influence of within-parish similarity level on between-parish similarity pattern.
abstract: We investigate the influence of within-parish similarity level on between-parish similarity pattern in surname analysis through a study of the relative roles of various isolation factors accounting for the population structure within a municipality (21 parishes) in the hilly part of northern Tuscany. One surname per family was collected (N = 3052), and the pattern of kinship observed by isonymy was compared with the expected patterns based on demogeographic variables. The fit of the isolation by distance model is substantially improved with the inclusion of values at zero geographic distance (i = j). Differentiation in migration rate was clearly shown by the local kinship values, which are highly correlated with the demogeographic features of the parishes under study. Furthermore, the strong heterogeneity of the local kinship values seems to be the major factor responsible for the poor relation of the off-diagonal values of the kinship matrix to the expected isolation pattern. In fact, the kinship matrix weighted on the basis of the local kinship values points to a pattern of similarity among parishes congruent with the demogeographic structure of the population. On the whole, the results indicate that at the low hierarchical level of parishes the extreme localization of surnames is a disturbing factor in population structure analysis. A simple method to overcome this problem has been proposed.
authors.affiliation: Dipartimento di Scienze del Comportamento Animale e dell'Uomo, Università di Pisa, Italy.
authors.forename: M G
authors.initials: MG
authors.lastname: Franceschi
authors.forename: G
authors.initials: G
authors.lastname: Paoli
mesh_terms: D000531:Altitude; D000704:Analysis of Variance; D003710:Demography; D005819:Genetic Markers; D014644:Genetic Variation; D005828:Genetics, Population; D006801:Humans; D007558:Italy; D008962:Models, Theoretical; D009275:Names; D014171:Transients and Migrants
chemical_list: D005819:Genetic Markers