Chromosomal mapping was first carried out by

While working on Drosophila in Morgan’s laboratory, Sturtevant did work on recombination frequency based on results of intercrossing between dihybrids with the help of formula Number of recombinants/ total number individuals formed multiplied by 100. 1% recombination is one map unit or one Morgan or Centimorgan. Based on this formula he mapped the genes on X chromosome of Drosophila.