Lab: Mouse Genetics (One Trait) Answers

In steps 4 and 5, you reversed the process. You were shown the parents and offspring above. You did a to identify the genotypes of the parents

parents and predicted the fur color, or , of the offspring.

If you did the experiment again, how could you improve upon the experimental design? Check all that apply.

Therefore, both parents pass the B✔ bbb allele to every offspring.

When you combine two of these alleles, the resulting genotype is ✔ bbBBBb; therefore, the resulting offspring have white fur.

You confirmed the above in steps 1 through 3, in which you changed the of the parents and predicted the fur color, or , of the offspring.

In general, did the simulated mice align with your predictions from the Punnett squares?

If you crossed two mice with white fur, what distribution of fur color would you expect in the offspring?

In the cross Bb x Bb (two heterozygous mice), what percentage of the offspring would you predict to have the same phenotype as the parents?

There are genes that govern the eye color of mice, too. Suppose that a true-breeding mouse with red eyes is crossed with a true-breeding mouse with black eyes. All of the offspring mice have black eyes. What can you conclude?

Your prediction is that of the offspring would have the dominant phenotype, and of the offspring would have the recessive phenotype.

What is the probability that the couple would have a child that was also a carrier for sickle cell anemia?

Error Analysis: What might be the reason that some of your percentages didn’t exactly match your predicted results?

Justify your answer by filling in the blanks. Both parents have white fur. OneThe most likely✔ The only

Next, you perform a cross with a mouse with black fur and a mouse with white fur. Which result(s) for the offspring would confirm that the mouse with black fur was heterozygous?

Suppose that you had a male mouse with black eyes and a female mouse with red eyes. You know that the allele for black eyes is dominant, and you want to determine whether the male is heterozygous. To do so, you would do a . Breed them and look for approximately a ratio of black eyes to red eyes.

0%✔ 25%50%75%

way that this can happen is if their genotypes are both ✔ bbBBBb.

them and look for approximately a 100% to 0%75% to 25%✔ 50% to 50%25% to 75%0% to 100% ratio of black eyes to red eyes.