A cow that is heterzygous for the black coat allele is crossed with a bull that is homozygous for the red coat allele. Which of the following Punnett squares represents this cross?
A. B B
b Bb Bb
b Bb Bb That's one punnett square
B. B b
B BB Bb
b Bb bb That's one punnett square
C. B b
b Bb bb
b Bb bb That's one punnett square
D. B b
B BB Bb
B BB Bb That's one punnett square
Is the answer c?
Punnet square A is correct.
To determine the Punnett square that represents the cross between a heterozygous black coat allele cow and a homozygous red coat allele bull, you need to understand how alleles are inherited.
In this case, "B" represents the black coat allele, and "b" represents the red coat allele. Heterozygous means having two different alleles, so the cow's genotype is "Bb." Homozygous means having two identical alleles, so the bull's genotype is "bb."
To create a Punnett square, you need to combine the alleles from one parent with the alleles from the other parent. In this case, since the cow's genotype is "Bb" and the bull's genotype is "bb," you would put the "B" and "b" alleles from the cow horizontally and the "b" alleles from the bull vertically.
Let's go through the options provided:
A. B B b Bb b Bb
b Bb b Bb b Bb
B. B b B BB b Bb (This Punnett square is incorrect because the bull should have a "b" allele instead of a "B" allele)
b Bb b Bb b bb
C. B b b Bb b bb
b Bb b Bb b bb (This Punnett square is correct)
D. B b B BB b Bb (This Punnett square is incorrect because all the offspring should be heterozygous like the cow)
B BB B BB b BB
Therefore, the correct Punnett square for the cross between a heterozygous black coat allele cow and a homozygous red coat allele bull is option C.