In the given scenario, the allele B (black coat) is dominant, and the allele b (spotted coat) is recessive. For a dog to exhibit a spotted phenotype, it must have the genotype that expresses the recessive trait, which is "bb."
Here's a simple Punnett square to demonstrate the possible genotypes from a cross. Assuming we are looking at a cross between a homozygous recessive (bb) dog and a heterozygous (Bb) dog:
B | b
----------------
b | Bb | bb
----------------
b | Bb | bb
From the Punnett square:
- 50% of the offspring will be Bb (black coat)
- 50% of the offspring will be bb (spotted coat)
Thus, only the genotype "bb" leads to a spotted phenotype.
Answer:
The genotypes for this dog breed that would lead to a spotted phenotype is bb.