Heterozygous with a Recessive

In Dachshunds Black is dominate, Chocolate recessive.

If you cross a heterozygous Black Dachshund with a Chocolate Dachshund, what would be the genotypes and phenotypes?

1. The first thing that we need to do is set up a interpretation key.

   BB or Bb = Black, bb = Chocolate

   
   
   
2. Then we determine the genetic cross in the problem.
   
   Bb X bb, Heterozygous crossed with a homozygous recessive
   
   
3. Next we draw the square, and place the genes. One gene in each column, and one for each row.
   
   

   	B	b
   b
   b

   
   
   
4. We take the letter at the top of each column and place it in each square below
   
   

   	B	b
   b	B	b
   b	B	b

   
   
   
5. We take the letter at the front of each row and place it in each square next to it.
   
   

   	B	b
   b	Bb	bb
   b	Bb	bb

   
   
   
6. Now we determine the genotypes and the phenotypes.
   
   

   Ratio	Genotype	Ratio	Phenotype
   2/4	Bb	2/4	50% Black
   2/4	bb	2/4	50% Chocolate