A yellow female Labrador retriever was mated with a brown male. Half of the pupp

Question

A yellow female Labrador retriever was mated with a brown male. Half of the puppies were brown, and half were yellow. Explain how the same female, when mated with a different brown male, could produce only brown offspring. O The firsf male was bb Ee, and the second male was bb ee. O The first male was bb Ee, and the second male was Bb Ee. O The first male was bb Ee, and the second male was bb EE. O The first male was bb EE, and the second male was bb Ee. O The first male was Bb EE, and the second male was Bb Ee.

Explanation / Answer

Answer C) The first male was bbEe, and the second male was bbEE.

Solution) In the Labrador retrievers, there are varying two loci named as B and E.

When both the loci have dominant allele (B_E_), then it gives Black.

When only E loci have dominant allele and b loci as a recessive allele (bbE_), it gives brown dogs.

and having only B loci as dominant or both the recessive loci (B-ee or bbee), it gives yellow dogs.

Under such condition, the first brown male must be genetically heterozygous for the E locus but recessive for b loci: bbEe.

and yellow female had the genotype as bbee. so, the puppies from their cross would be 1/2 brown (bbEe) and 1/2 Yellow (bbee).

But, in the second cross, we obtain only brown puppies. therefore, the second brown male must be genetically homozygous for both the loci as bbEE. In such cross, all the puppies will be brown (bbEe).

NOTE: We do not have any black puppy in the second cross, so the second male can't be B_E_.

Therefore, the correct answer is option C) The first male was bbEe, and the second male was bbEE.

Related Questions

Navigate

• Browse (All)
• Browse A
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.