Scheme showing the final reduction in the region bearing factor 1. Summary of results pairing genotype to phenotype. Genotype on each marker site is represented by "M" for D. mauritiana and "S" for D. simulans. Phenotype was divided in two categories: quasi-sterile gave 9.0 offspring on average (± 2.32) and fertile gave 215.4 offspring on average (± 24.51). The clear-cut localization of factor 1 ranges in between markers pos5279 and pos14460, a region of approximately 9 kb.