Genetics Problem ...?

Question

The allele for black coats (in a dog) is dominant to the allele for chocolate coats. A heterozygous dog is crossed to a dog with chocolate coat. What coat color/s will the offspring have? What is the expected frequency of each color?

We have to make a Punnett Square...

There is a couple who are both heterozygous for sickle cell anemia. If they have children, what would their genotypes and phenotypes be? What are the expected frequencies of each genotype and phenotype?

---is it 75% they will have it, and 25% they will not??

Answer 1

Black coats = B

Chocolate coats = b

heterozygous = Bb crossed with chocolate = bb

Bb X bb

Your four square would be Bb, Bb, bb, bb.

Genotype is 50% Bb and 50% bb

Phenotype is 50% Black and 50% chocolate

Anemia:

No sickle cell = A

Sickle cell = a

Aa X Aa

Punnett square gives you AA, 2Aa, and aa

Genotype: 25% AA, 50% Aa, 25% aa

Phenotype: 75% No sickle cell and 25% sickle cell

Answer 2

Black coats = B

Chocolate coats = b

heterozygous = Bb crossed with chocolate = bb

Bb X bb

Your four square would be Bb, Bb, bb, bb.

Genotype is 50% Bb and 50% bb

Phenotype is 50% Black and 50% chocolate

Anemia:

No sickle cell = A

Sickle cell = a

Aa X Aa

Punnett square gives you AA, 2Aa, and aa

Genotype: 25% AA, 50% Aa, 25% aa

Phenotype: 75% No sickle cell and 25% sickle cell

glad i helped