Use the following information to answer the next question.The Labrador Retriever’s coat colours are black, yellow, and chocolate.Yellow is produced by the presence of a recessive epistatic gene, which has the effect of masking the black and chocolate colour genes. Black (B) is dominant to chocolate (b). Therefore, the possible genotypes and corresponding phenotypes are:
Phenotype Possible Genotypes Black G__B__ Brown G__bb Yellow gg__Predict the percentage of offspring that would be black in colour for each of the following crosses. Record your answer as a whole number.
Cross: GgBbGgBB GGBbGGBb Percentage ofOffspring: Answer% Answer%
6 years ago
Answered By Olena V
In both cases the chances of having a Lab Retriever with a black coat is 75%.
To solve this question I have created a Punett square for the combination of GgBb x GgBB. Because there are two genes for each genotype there are 4 possible combinations that could result in the breeding of the individuals GgBb and GgBB. As you can see for the individual GgBb the possible combinations that could be passed on to their offspring are; GB, Gb, gB and gb. You know right away that any combination of genes with GB will result in offspring with a black coat because G means that there is no possibility of yellow offspring and B is the dominent gene for black.
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