where to retrieve the genetic map.
Can be an object of SimParam or
MapPop-class. If NULL, the function will
look for a SimParam object called "SP" in your
global environment.
sex
determines which sex specific map
is returned. Options are "A" for average map, "F"
for female map, and "M" for male map. All options are
equivalent if not using sex specific maps or using
pulling from a MapPop.