To determine the genotypes that would result in a spotted phenotype for this dog breed, we need to consider how the alleles work. The black coat allele (B) is dominant, while the spotted coat allele (b) is recessive.
The only genotype that can lead to a spotted phenotype is bb, as it is the only combination that does not have the dominant B allele.
Punnett Square
Let's create a Punnett square to visualize the possible genotypes from two parents:
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If we cross two homozygous black coat (BB) dogs:
\[ \begin{array}{c|c|c} & B & B \ \hline B & BB & BB \ \hline B & BB & BB \ \end{array} \] All offspring will be BB (black coat). -
If we cross one black coat carrier (Bb) with another black coat carrier (Bb): \[ \begin{array}{c|c|c} & B & b \ \hline B & BB & Bb \ \hline b & Bb & bb \ \end{array} \] Offspring will be BB (black coat), Bb (black coat), and bb (spotted coat). Here, only 1 out of 4 will be bb (spotted).
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If we cross a black coat dog (B) with a spotted dog (bb): \[ \begin{array}{c|c|c} & B & b \ \hline B & Bb & Bb \ \hline b & bb & bb \ \end{array} \] In this case, 2 out of 4 will be Bb (black coat) and 2 out of 4 will be bb (spotted coat).
Conclusion
The only genotype that results in a spotted phenotype is bb.
So, the answer to your question regarding the genotypes that lead to a spotted phenotype is bb.