Description
Have you had a hard time creating ideal results from "crosses" done in your classroom? Most class demonstrations of probability in genetics rely on too small of a sample size to get consistent results. The digital part of this lab help students see and understand the importance of sample size.
Initially students will do the traditional coin flip to determine which alleles they will give their offspring. It is a heterozygous cross so it should give a 3:1 ratio, but often gives 2:1 or 4:1 with classes. Then I show students the google sheets and briefly explain how when I hit Roll/reset (The red box) which then randomly selects from the T or t allele for each parent. This process is repeated 1000 times with the click of a button. It is interesting to note that the yellow is "bursty", so if your sample has a "burst" then the ratio gets thrown off.
I then selected some cells to give me a rounded ratio from a certain sample size. These are displayed on the right. As you can see, the sample size of 50 or less tend to not get a 3:1 ratio. But the larger the better. I also did the same from a TT/tt cross to show how that should be a 1:1 ratio.
Genetics Simple Dominant/Recessive Coin Flip Model and Computer Simulation
Highlights
Description
Have you had a hard time creating ideal results from "crosses" done in your classroom? Most class demonstrations of probability in genetics rely on too small of a sample size to get consistent results. The digital part of this lab help students see and understand the importance of sample size.
Initially students will do the traditional coin flip to determine which alleles they will give their offspring. It is a heterozygous cross so it should give a 3:1 ratio, but often gives 2:1 or 4:1 with classes. Then I show students the google sheets and briefly explain how when I hit Roll/reset (The red box) which then randomly selects from the T or t allele for each parent. This process is repeated 1000 times with the click of a button. It is interesting to note that the yellow is "bursty", so if your sample has a "burst" then the ratio gets thrown off.
I then selected some cells to give me a rounded ratio from a certain sample size. These are displayed on the right. As you can see, the sample size of 50 or less tend to not get a 3:1 ratio. But the larger the better. I also did the same from a TT/tt cross to show how that should be a 1:1 ratio.
