Question: Assume that r, red and sc, scarlet, are two recessive eye-color mutations that lie 20 map unites apart on the Drosphila X chromosome, and that each causes a read eye color in place of the wild type purple color.

1) If a female from a pure-breeding rr stock is mated with a red-eyed (sc) male, what phenotypes will the F1 sons and daughters display?

2) If these F1 flies are interbred, what will be the phenotypic ratios among F2 grandaughters and grandsons?