**Estimating
demographic parameters from F-statistics**

**J. Goudet**

Dept. Ecology & Evolution, Biophore, UNIL-Sorge, CH-1015, Lausanne -
SUISSE

Inferring demographic parameters
from genetic data is a long standing goal of population genetics. Most students of population genetics would
say that genetic data allows estimation of "average" demographic
parameters, and often as a product of two variables. Typical examples are the
estimation of the parameter, proportional to the number of mutants entering
each generation in the population, or the number of migrants Nm from FST. In
addition to estimate "average" demographic parameters, these
estimations are strongly dependent on the model from which they are derived,
and on equilibrium conditions.

Here, I will show that if one divides a life
cycle in its different elements, and obtain the transition in gene identities
(simple function of gene diversities) between the different life stage,
instantaneous estimation of migration and effective population size can be
obtain, providing that samples from the different life stages have been
genotyped. I will illustrate this
method using data from the common shrew, *Crocidura
russula*, where we have been able to estimate dispersal rates of males and
females as well as effective population size. I will conclude by discussing
possible developments of the method, which might be of interest to mycologists.