If a breeder wanted to discover whether a black guinea pig was homozygous (BB) or heterozygous (Bb) for coat color, the animal in question could be crossed with an individual with what phenotype?
Whatever bb stands for, that is the one you would use as a mate. If the Black guinea pig was Bb, about half of the offspring would show the b phenotype — whatever that is. If BB, all of the offspring would be black.
You can verify this by using the Punnett square.
http://en.wikipedia.org/wiki/Punnett_square
http://anthro.palomar.edu/mendel/mendel_2.htm
I hope this helps. Thanks for asking.
BB
To determine whether a black guinea pig is homozygous (BB) or heterozygous (Bb) for coat color, it can be crossed with an individual exhibiting the recessive phenotype. In this case, the suitable choice would be a white guinea pig (bb). By crossing the black guinea pig (either BB or Bb) with a white guinea pig (bb), the breeder can observe the phenotypic characteristics of their offspring to deduce the genotype of the black guinea pig.
To determine whether a black guinea pig is homozygous (BB) or heterozygous (Bb) for coat color, it can be crossed with an individual that has a known coat color genotype. In this case, the breeder could cross the black guinea pig with a guinea pig that has a known homozygous recessive genotype for coat color, such as a white guinea pig (bb).
By performing this cross, the breeder can observe the coat color of the offspring and draw conclusions about the genotype of the black guinea pig. Let's see how the results may help determine if the black guinea pig is homozygous (BB) or heterozygous (Bb) for coat color.
If the black guinea pig is homozygous (BB) for the black coat color, all the offspring from the cross will inherit one dominant black allele from the black guinea pig and one recessive white allele from the white guinea pig. As a result, all the offspring will have black coats.
If the black guinea pig is heterozygous (Bb) for the black coat color, half of the offspring will inherit the dominant black allele from the black guinea pig and the other half will inherit the recessive white allele from the white guinea pig. Consequently, approximately 50% of the offspring will have black coats, while the other 50% will have white coats.
By carefully observing the coat color of the offspring from this cross, the breeder can determine whether the black guinea pig is homozygous (BB) or heterozygous (Bb) for coat color based on the ratio of black to white-coated offspring.
Therefore, crossing the black guinea pig with a white guinea pig will provide the necessary information to decipher the coat color genotype of the black guinea pig.