SIMPLE METHOD FOR CALCULATING CONFIDENCE-LIMITS AROUND INBREEDING RATE AND EFFECTIVE POPULATION-SIZE ESTIMATES FROM PEDIGREES

An important concept in population genetics is effective population size (N(e)), which describes the expected rate of loss of genetic variability from a population. One way to estimate N(e) is using a pedigree. However, there are no methods for comparing the N(e) estimated from a pedigree with that expected from life-history models. In the paper we show how N(e) can be estimated from the change in inbreeding rate (f) estimated from a pedigree. The mean individual inbreeding rate in a population at a given time must be calculated from averaged values for males and females, where each age class is weighted by its reproductive value. We show an exact method for placing confidence intervals around f and N(e) using a binomial distribution, and present a method for approximating this interval for large N(e)S using a Poisson distribution. These confidence intervals can be used to compare f and N(e) from a pedigree to expected values from demographic models, and to compare N(e)S of two populations.