How many polymorphic genes will it take to span the human genome?

It is desirable to know how many polymorphic marker loci will be required so that every human genetic locus can be mapped by classical pedigree methods to a specific region of a specific chromosome. Assuming a total autosomal map length of 33 morgans, it would take only about 33/(2d) evenly spaced markers for every locus to be within d morgans of a marker. Taking into account that the markers will fall randomly along the genome, we show that a much larger number of such loci will have to be isolated and tested before the goal of a saturated gene map is reached.