Random Assortment

• This is a great place to start since random assortment occurs within an individual parent during meiosis but before fertilization takes place.
• Individual gametes produced through meiosis have one set of chromosomes. The chromosomes comprising the set are a random mix or "assortment". Some came from the persons mother and some from the father.
• Thus, during fertilization the zygote actually inherits a mix of all four of its grandparents chromosomes.
• In essense, nothing controls or guides the paired homologs as to what side of the metaphase plate they end up on.
• You'll see what this means by doing this lesson.
• So how do chromsomes randomly assort?

Complete the following steps for this lesson:

1. Click here to see how to set up your drawing board paper.

2. Run the animation.

3. What stage(s) of meiosis is being shown in the animation?

a. prophase I and metaphase I

b. prophase II and metaphase II

c. telophase I and cytokinesis

d. anaphase II and telophase II

Check your answer

4. The final image of the animation showing one possible assortment is given below. Draw two other possible combinations of random assortment.

Check your answers. The greenies below will each exhibit two windows. One window is an animation and the other is the final frame image. They will overlap but you can spread them apart to view them side by side.

There is one more possible combination. What is it?

5. For each of the three combinations above, draw the four possible gametes after meiosis. (help)

Check your answer