Question

A homozygous brown mouse mates with a heterozygous brown mouse . The allele for brown fur (B) is dominant over the allele for tan fur (b) what percentage of the offspring will mostly likely have brown fur

Answer 1

When a homozygous brown mouse (BB) mates with a heterozygous brown mouse (Bb), all of the offspring (100%) will have brown fur since brown is dominant over tan fur.

Step-by-step explanation:

When a homozygous brown mouse (BB) mates with a heterozygous brown mouse (Bb), we can predict the proportion of offspring that will likely have brown fur using a simple Punnett square. The homozygous mouse can only contribute a B allele, and the heterozygous mouse can contribute either a B or a b allele. Setting up the Punnett square, the possible genotypes for the offspring are:

• 
  
• BB (homozygous brown)
• 
  
• Bb (heterozygous brown)

Since the allele for brown fur (B) is dominant over the allele for tan fur (b), both BB and Bb genotypes will result in brown fur. Therefore, all offspring (100%) will likely have brown fur as there's no chance for a bb genotype which would result in tan fur.