Question

# In guinea pigs, black coat (B) is dominant over white (b). If a homozygous black animal...

In guinea pigs, black coat (B) is dominant over white (b). If a homozygous black animal is crossed with a white animal, what will be the appearance of their offspring? Give the genotypic and phenotypic ratios

The phenotype ratio of the offspring is

 1:1 3:1                                                           1:2:1 4:0

2. The genotype ratio of the offspring is _____________

1. 1:1
2. 3:1
3. 1:2:1
4. 4:0

In summer squash, white fruit (W) is dominant over yellow fruit (w).

3. If a squash plant homozygous for white is crossed with one homozygous for yellow, what would be the phenotype of the offspring?

 Ww WW               ww white yellow

4. The genotype of the offspring is _____________

1. Ww
2. WW
3. ww
4. white
5. yellow

Since Black colour is dominant over white,

Genotype of Black guinea pig- BB (Homozygous dominant) or bb (Heterozygous dominant)

Genotype of white guinea pig- bb (Homozygous recessive)

Cross:- BB × bb

 B B b Bb (Black) Bb (Black) b Bb (Black) Bb (Black)

So, Genotypic ratio= 1:1

And Phenotypic ratio= 1:1

Answer 2. a. 1:1 (explanation above)

Since white colour is dominant over yellow colour,

Genotype of White colour- WW (homozygous dominant) or Ww (heterozygous dominant)

Genotype of yellow colour- ww (homozygous)

Cross:- WW × ww

 W W w Ww (white) Ww (white) w Ww (white) Ww (white)

So genotype of offsprings= Ww

Phenotype of offsprings= White

Answer 4. a. Ww (explanation in the above part)