To solve this problem, let's break down the genotype BbRr and identify the possible combinations of alleles that could be present in the gametes.
An organism with the genotype BbRr is heterozygous for both traits, meaning it has one dominant allele and one recessive allele for each trait. The principles of Mendelian genetics tell us that during gamete formation, the alleles for each gene segregate independently, which is known as the principle of independent assortment.
Here’s the step-by-step process to determine the possible genetic combinations:
1. Identify the possible alleles for each trait:
- For the first trait (B/b), the organism has alleles B and b.
- For the second trait (R/r), the organism has alleles R and r.
2. Determine the possible combinations of alleles:
- Each allele from the first trait can pair with each allele from the second trait.
- B can go with R or with r.
- b can go with R or with r.
3. List all possible combinations:
- B with R makes the combination BR.
- B with r makes the combination Br.
- b with R makes the combination bR.
- b with r makes the combination br.
So, the possible allele combinations in the gametes of a BbRr organism are:
[tex]\[ \text{BR, Br, bR, br} \][/tex]
Therefore, the answer that best demonstrates the possible genetic combinations that could be present in a gamete cell of the organism is:
[tex]\[ \boxed{B R, B r, b R, b r} \][/tex]
