Please consider the following question:
You cross Drosophilia and receive the following offspring: 965 wild-type, 944 black- vestigial, 206 gray- vestigial, and 185 black- normal. Explain your results and give the recombination frequency.
I would like to know how to determine what the parental type is here so I can then find the recombination frequency. I know that recombination frequency is equal to the total number of recombinants divided by the total number of offspring. In order to determine the total number of recombinants I must know the parental types. My teacher stated that the parental types are the ones that are most prevalent in number after a cross, but there are occasions in which this does not work.
Is there a more 'concrete' way to determine which are the parental types?