In Cats, Short Hair (H) is dominant to , Long hair (h). Tabby (T) is dominant to
ID: 198228 • Letter: I
Question
In Cats, Short Hair (H) is dominant to , Long hair (h). Tabby (T) is dominant to , Stripless (t). Normal, no colorpoint (N) is dominant to, Colorpoint (n).
I. A homozygous short hair, homozygous stripeless cat and a homozygous long hair, homozygous tabby cat have kittens.
a. Draw the Punnett Square (4x4 square).
b. What is the phenotype ratio?____________________________
c. What percentage of the offspring will have short hair and be stripeless? _____________
II. A heterozygous tabby, heterozygous normal cat and a homozygous stripeless, homozygous colorpoint cat have kittens.
a. Draw the Punnett Square (4x4 square).
b. What is the phenotype ratio?____________________________
c. What percentage of the offspring will be tabby and colorpoint? _____________
d. What percentage of the offspring will have stripeless and normal? _______________
III. A solid colored, short-haired female rabbit (ssHH) is mated to a spotted, long-haired male rabbit (SShh).
a. Draw the Punnett Square.
How many out of 16 will be expected to be spotted with long hair? ________________________
How many out of 16 will be expected to be spotted with short hair? ________________________
Explanation / Answer
I.
a. HHtt x hhTT
Gametes from HHtt : Ht, Ht, Ht, Ht
Gametes from hhTT : hT, hT, hT, hT
Punnett Square Analysis:
b. The Punnett square analysis shows that all kittens will have short hair and be tabby.
So the phenotypic ratio is: 4:0
c. 0% of the offspring will have short hair and be stripeless.
II.
TtNn x ttnn
Gametes from TtNn : TN, Tn, tN, tn
Gametes from ttnn : tn, tn, tn, tn
Punnett square analysis:
TtNn (Tabby and normal)
b. The phenotypic ratio is 1:1:1:1
c. 25% of the offspring will be tabby and colorpoint.
d. 25% of the offspring will have stripeless and normal.
III.
ssHH x SShh
Gametes from ssHH: sH, sH, sH, sH
Gametes from SShh: Sh, Sh, Sh, Sh
The above Punnett square analysis shows that all offspring will be spotted and will have short hair.
Out of 16, no offspring are expected to be spotted with long hair.
All 16 offspring are expected to be spotted with short hair.
Ht Ht Ht Ht hT HhTt HhTt HhTt HhTt hT HhTt HhTt HhTt HhTt hT HhTt HhTt HhTt HhTt hT HhTt HhTt HhTt HhTt