Slide showing a table illustrating 'mutations in different directions at the white locus in drosophila melanogaster' (fruit fly). Slide shows a table illustrating 'mutations in different directions at the white locus in drosophila melanogaster'. Title of slide reads: 'Table 4. - Mutations in different directions at the white locus in drosophila melanogaster. Treated adult males, circa 4800 r. (Timofeeff-Ressovsky, 183).' Top row headings: 'Mutations to from', 'w', 'wbf', 'we', 'wa', 'wb', 'wx', 'W', 'Number of treated gametes' and 'Total percentage'. Left column headings: 'Mutations to from', 'W', 'wco', 'wb', 'wc', 'wa', 'we', 'wbf', 'wt', 'w', 'total'. Late 19th to early 20th century