Sturtevant's hypothesis:
Frequency of cross-overs during meiosis is related to the distance between genes; the greater the distance, the greater the frequency of cross-overs

Sturtevant's experiments:
studied linked traits in fruit flies & recorded the percentage of times that cross-overs occurred & then used those cross-over frequencies to make linkage maps

Making a linkage map:
*Cross-over frequencies (recombinant frequencies) = approximate distance on chromosome
* by knowing all cross-over frequencies the relative locations of the genes can be determined