Exciting Genetic Traits in Mice!
What are the chances of an offspring mouse having black fur and red eyes?
What genotype should be tested to determine the probability of an offspring having specific traits?
Answer:
The probability of an offspring mouse having black fur and red eyes can be determined by understanding the genotype of the parent mice involved. In this case, a test cross with a bb (white fur aggregate) genotype can help determine the likelihood of offspring inheriting certain traits.
When a ff ee mouse is bred to a ff ee mouse, the offspring will all have black fur since all of them will have at least one dominant allele for black fur, which will override any allele for brown fur.
The color of a mouse's fur is influenced by the alleles they inherit for the MC1R gene. Mice with two copies of allele 1 have the lightest fur, those with two copies of allele 2 have the darkest fur, and heterozygotes have an intermediate fur color.
Through a test cross with a bb genotype, if all offspring mice are dark (Bb), then it can be deduced that the genotype for dark fur is BB, ensuring that all offspring will have black fur.