  We review the statistical properties of the genealogies of a few models of
evolution. In the asexual case, selection leads to coalescence times which grow
logarithmically with the size of the population in contrast with the linear
growth of the neutral case. Moreover for a whole class of models, the
statistics of the genealogies are those of the Bolthausen-Sznitman coalescent
rather than the Kingman coalescent in the neutral case. For sexual
reproduction, the time to reach the first common ancestors to the whole
population and the time for all individuals to have all their ancestors in
common are also logarithmic in the neutral case, as predicted by Chang []. We
discuss how these times are modified in a simple way of introducing selection.
