Question

For all questions, assume that you have genes for beak color, tail-feather length, and feather color all linked (located) on the same chromosome, but you don't know the order of the genes on the chromosome or the distance between them. The alleles for these genes are
beak color: Y for yellow beak (YY and Yy) and y for black beak (yy)
tail-feather length: L for long tail (LL and Ll) and l for short tail (ll)
feather color: B for blue feathers (BB and Bb) and b for white feathers (bb)

Answer 1

Cross a YyLl (heterozygous parent with dominant traits) with yyll (homozygous parent with recessive traits). Look at the number of phenotypes of the F1 generation:
YyLl: 400
Yyll: 100
yyLl: 100
yyll: 400

Answer 2

1. Cross one parent that is heterozygous for both beak color and feather color with a parent that is homozygous for both recessive traits. What are the genotypes of the parents? (Hint: Recall that the P generation includes a heterozygous parent with dominant traits and a homozygous parent with recessive traits.)