Pollen grains developing in presence of dominant Ms21 are defective and nonfunctional if sks1, normal if Sks1. Genetic 2005 2 coordinates determined from these recombination and map data: fl1 -10- sks1; ts1 -8- sks1; ts1 -11- sks1; see MaizeGDB ID: 934751; 934752; 934753. This gene was originally curated in MaizeGDB Database and the map position was displayed on the maize bins map if feasible.