  For a highly beneficial mutant $A$ entering a randomly reproducing population
of constant size, we study the situation when a second beneficial mutant $B$
arises before $A$ has fixed. If the selection coefficient of $B$ is greater
than the selection coefficient of $A$, and if $A$ and $B$ can recombine at some
rate $\rho$, there is a chance that the double beneficial mutant $AB$ forms and
eventually fixes. We give a convergence result for the fixation probability of
$AB$ and its fixation time for large selection coefficients.
