3 problems?

Question

#1 )In the garden pea, Mendel found that yellow seed color was dominant to green and round seed shape was dominant to shrunken. Determine the phenotypic and genotypic ratios for the F1 generation if a plant with homozygous rounded yellow seeds is crossed with a plant with shrunken green seeds.

#2) Tall tomato plants are produced by the action of a dominant allele T and dwarf plants by its recessive allele t. Hairy stems are produced by a dominant gene H and hairless stems by its recessive allele h. A heterozygous tall, hairy plant is crossed with a dwarf hairless tomato plant. Determine the phenotypic ratio for the F1 generation.

#3) The genotype of F1 individuals in a tetrahybrid cross is AaBbCcDd. Assuming independent assortment of these four genes, what are the probabilities that F2 offspring will have the following genotypes:

a. aabbccdd
b. AaBbCcDd
c. AABBCCDD
d. AaBBccDd

Answer 1

1. YYRR x yyrr
F1 YyRr genotype all yellow round phenotype
F2 YYRR 1/16 YYRr 2/16 YYrr 1/16
YyRR 2/16 YyRr 4/16 Yyrr 2/16
yyRR 1/16 yyRr 2/16 yyrr 1/16
Phenotypes: yellow round 9
yellow shrunken 3
green round 3
green shrunken 1
2. TTHH x tthh
F1 TtHh genotype all tall hairy phenotype
F2 genotypes and phenotypes will segregate just like no. 1

3.
a. 1/256
b, 16/256
c. 1/256
d. 4/256