The crosses that the question refers to are given in the table below:
| Parents | Progeny | |||
| Cross | ? | ? | F 1 | F 2 |
| 1 | L | W | ?W | ?1/2L, 1/2W |
| ?W | ?W | |||
| 2 | W | L | ?L | ?1/2W,1/2L |
| ?W | ?1/2W,1/2L |
The different sex-specific phenotypes found in the F1 show sex-linkage. The F1females inherit the phenotype of the fathers. In the first cross, we can understand that wild-type large spots are dominant over the lacticolor small spots.
We will consider 'A' as dominant wild type and 'a' as recessive lacticolor.
In cross 1, we can assume male to be the hemizygous sex, the predictions do not match the observations.
Parents - a/a female × A/Y male
F1generation- A/a females with wild type large spots
a/Y males with laticolor small spots
So, we will assume that the female is the hemizygous sex. The sex-determining chromosome in females can be called Z. So, the cross is
Parents a/Z female × A/A male
F1generation A/a wild type male
A/Z wild type female
F2generation A/Z wild type females 1/4
A/- wild type males 1/2
a/Z lacticolor females 1/4
Cross 2: The cross is between A/Z female × a/a
F1 generation a/Z laticolor females, A/a wild type males
F2 generationA/Z wild type females -1/4
A/a wild type males -1/4
a/Z lacticolor females 1/4
a/a lacticolor males 1/4
Therefore, the predictions match the observations.