  In this work, we develop excursion theory for the Wright-Fisher diffusion
with recurrent mutation. Our construction is intermediate between the classical
excursion theory where all excursions begin and end at a single point and the
more general approach considering excursions of processes from general sets.
Since the Wright-Fisher diffusion has two boundary points, it is natural to
construct excursions which start from a specified boundary point, and end at
one of two boundary points which determine the next starting point. In order to
do this we study the killed Wright-Fisher diffusion, which is sent to a
cemetery state whenever it hits either endpoint. We then construct a marked
Poisson process of such killed paths which, when concatenated, produce a
pathwise construction of the Wright-Fisher diffusion.
