4.02 Predicting Genetic Crosses

That's Joe. He's one of our animal breeders, and he's going to take us behind the scenes to show us how scientists predict traits in offspring of the animals that they breed. Besides breeding horses, a part of Joe's job is to have the petting zoo stocked up with all kinds of cute, cuddly creatures for the kids.

Take the miniature horse, for example; we kept breeding for short legs until we got a tiny horse. The same basic breeding principles that farmers use are carried out here to make sure that we have a wide variety of wonderful animals at the petting zoo. Now, as you know, animals have genes for all sorts of traits, such as hair color, and leg length just to name a few. We breed animals together that have the same traits we would like the offspring to have.

Over here in the rabbit area, we run a video in which Joe explains more about inherited traits and talks us through a breeding experiment using rabbits instead of peas.

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Gregor Mendel's Rules of Heredity: Using Punnett Squares (05:04)

That's a lot to absorb! Take a minute and catch up on your Travel Log. To successfully predict traits in offspring, you need to understand these terms. Add them to your vocabulary page for this module and be sure to put them in your notebook. (Click the term to see the definition.)

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Here is a parting souvenir for you all, a copy of Punnett's Square Notes.

Check it out. We found this in one of our vaults. This is priceless. Don't forget, the same principles that applied back then still hold today.

You will definitely want to print and read this page. Take a highlighter to it too! Add sticky notes or notes about ideas that you remember from your reading and the video!

Now you practice!

Complete the interactive Punnett Square practice problems at the first page that loads: Drag and Drop Genetics

Or you can watch the video. On the page that loads, look at the top-most right-hand corner.

Remember you can refer to the Punnett Square Notes to help you with this!

Lion, Tigers, and Ligers...Oh my!

Can you always tell a tiger by its stripes?

What would happen if you bred a lion and a tiger together? Would the combination have stripes or no stripes? Joe tells me that stripes are dominant, so we can use a Punnett square to answer a question.

Explore a wild cross by crossing lions with tigers:

Click Here to begin the activity

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Congratulations you did it!
These new animals are called ligers and only a few lucky people have ever seen this animal.

Looks like you are a pro now….So here is your chance to experiment with your own dragon breeding program. Explore how you can determine the phenotype of the dragons by changing their genotypes! Have some fun, but come back soon to move on!

Biologica's Web Lab: Genotype and Phenotype

Move on to the Travel Log and you can practice with some of your traits!