Thus the symbol
PART II. NEW DATA.
WHITE.
([Plate II], figure 11.)
The recessive character white eye-color, which appeared in May 1910, was the first sex-linked mutation in Drosophila (Morgan, 1910a, 1910b). Soon afterwards (June 1910) rudimentary appeared, and the two types were crossed (Morgan, 1910c). Under the conditions of culture the viability of rudimentary was extremely poor, but the data demonstrated the occurrence of recombination of the factors in the ovogenesis so that white and rudimentary, though both sex-linked, were brought together into the same individual. The results were not fully recognized as linkage, because white and rudimentary are so far apart in the chromosome that they seemed to assort freely from each other.