Intergenerational correlation of effective family size in early Quebec (Canada)

The use of a comprehensive demographic database of the early French Canadia n population (1608-1800) reveals an almost null impact of parents' fertilit y on children's fertility (r similar or equal to 0.01-0.05), which contradi cts the commonly held view that family size has a tendency to run in famili es. However, in this population, there is a clear transmission from one gen eration to the next of the effective family size within a given geographica l area (EFS, defined as the number of children that settle per settled indi vidual). Three types of correlations between EFS of parents and children ar e presented in order to account for the impact of socio-demographic differe ntials. Individuals who belong to a large sibship and who settled in a give n subdivision tend to encourage the settlement of a high number of their ow n children in the same subdivision (r similar or equal to 0.1-0.3). An addi tional correlation was introduced to see if geographically-based differenti als of EFS can account for the differential of founders' regional genetic c ontribution. The analysis shows that EFS correlation has a definite impact on the concentration of a population's gene pool (it increases it by simila r or equal to 20%-45%), and partly accounts for the differences between sub divisions in this regard. (C) 2001 Wiley-Liss, Inc.