In general, did this method work well? What must be true to have offspring with red eyes and white fur? · Use the Gizmo to create two Ff Ee parents. What is the probability that an offspring mouse will have black fur and black eyes? Observe : Breed a black-fur, black-eye mouse with a white-fur, red-eye mouse. We recommend doing that activity before trying this one. What do you think is the most likely outcome? What percentage of offspring had black fur and red eyes? Fill in the Punnett square for each trait. Experiment : Check that Show statistics is turned on. Express each probability as a fraction and as a percentage.
Introduction: If two events are independent, the probability of both events occurring together is equal to the product of their independent probabilities. On your own : Try other parent combinations. How many offspring have black fur and red eyes? Gizmo Warm-up On the Mouse Genetics Two Traits Gizmo, drag mice into the Parent 1 and Parent 2 spaces, and then click Breed to see their offspring. What must be true to have offspring with black fur? Experiment : Click Breed, and record the genotypes of the offspring on a sheet of paper. How many offspring have white fur and red eyes? What do you expect the offspring of these mice to look like? Write the results in the table below. Move the cursor over a mouse to see its genotype, or allele combination.
How many offspring have white fur and black eyes? Predict : Now multiply the probabilities together to find the probability of black fur and red eyes. What must be true to have offspring with black eyes? Experiment : Turn on Show statistics. How many of the offspring had black fur and red eyes? Use the Gizmo to test your predictions. . Model : Each parent mouse will contribute one allele for fur color and another for eye color. Check that the parent mice genotypes are Ff Ee and Ff ee.
Model : To determine the probability of a trait combination such as black fur and red eyes, consider each trait separately. Experiment with different combinations of parent mice. What is the genotype of the white-fur parent? Probability can be expressed as a percentage, such as 75%, as a decimal 0. What are the genotypes of the offspring? Trait combination: Black fur, black eyes Black fur, red eyes White fur, black eyes White fur, red eyes Number: Percentage: 3. Fill in the empty spaces to complete the square. Compare each predicted percentage to the actual percentage.
How many offspring have black fur and black eyes? Click Breed several times, and then drag two of the offspring into the Holding Cages below. Analyze : How well did the results match the predictions of the Punnett square? Repeat this several times to see a variety of offspring. Be sure there are two Ff Ee parents. Question: What patterns appear when two traits are inherited? Express each probability as a fraction. Extend : Turn on Show statistics, and click Breed until there are 100 offspring. What must be true to have offspring with red eyes? Question: How can a 4x4 square model the inheritance of two traits? Predict : Click Clear, and move the two mice from the Holding Cages into the parent box. What is the genotype of the black-fur parent? A single coin is flipped four times.
Click Breed until there are 500 offspring. What must be true to have offspring with white fur? Then determine the probability of black fur and the probability of red eyes. The combinations are written along the top and sides of the expanded Punnett square, as shown below. Click Breed until there are 500 offspring. Analyze : The probabilityof an event is the likelihood that it will happen.
· Use the Gizmo to create an Ff Ee parent and an Ff ee parent. . . . . . .
. . . . . .
. . . . . . .