In a certain dog breed, the allele B for a black coat is dominant, and the allele b for a spotted coat is recessive. What genotypes for this dog breed would lead to a spotted phenotype? **Make a Punnet square for help**
To determine the genotypes for a spotted phenotype, we can use a Punnett square. Let's assume that the dominant allele for a black coat is represented by "B" and the recessive allele for a spotted coat is represented by "b".
With this information, there are two possible genotypes that would lead to a spotted phenotype:
1. Homozygous recessive: bb
2. Heterozygous: Bb
Punnett square:
| B | b |
------------|--------|-------|
B | BB | Bb |
------------|--------|-------|
b | Bb | bb |
In this Punnett square, the possible genotypes of offspring are shown when two dogs with the given genotypes are crossed. As you can see, 25% of the offspring would have the genotype bb, resulting in a spotted coat phenotype. Additionally, 50% of the offspring would have the genotype Bb, demonstrating a heterozygous genotype but a black coat phenotype due to the dominance of the B allele.
so what's the answer
The genotypes that would lead to a spotted phenotype in this dog breed are:
1. Homozygous recessive: bb
2. Heterozygous: Bb
To determine the genotypes that would lead to a spotted phenotype in this dog breed, we can use a Punnett square.
First, let's assign the dominant allele B for a black coat and the recessive allele b for a spotted coat.
Now, we need to know the genotypes that would result in a recessive phenotype, which is a spotted coat (bb). A recessive phenotype will only appear if an individual has two copies of the recessive allele.
To make a Punnett square, we'll cross individuals with the genotypes Bb (one dominant and one recessive allele) and Bb (same genotype as before).
B b
---------------------
B | BB | Bb |
---------------------
b | Bb | bb |
---------------------
In the Punnett square, we can see that there are three possible genotypes that would lead to a spotted phenotype (bb): Bb, Bb, and bb.
By crossing two individuals with the genotype Bb, there is a 25% chance of obtaining the genotype bb and thus achieving a spotted coat phenotype.