Final Course

Discussion with Participants

Read or paraphrase:

• Ask participants who have dogs as pets to describe their pet. What color is its coat? How big is it? How long is their coat?

People have developed dog breeds as different from one another as a spotted, short-haired dalmatian and the solid-colored, long-haired collie. The many different breeds of dogs we have today are due to selective breeding. People decide which dogs to breed - that is, which dogs they want to have puppies. But, when you breed two dogs together, you don't have control over exactly what the puppies will look like because you can't control which genes are kept and which are lost.

Breeding allows genomes of parents to mix together and offspring obtain genes from both parents. This is especially noticeable when you breed two very different dogs, like a poodle and a cocker spaniel. Then you get a Cockapoo.

• Describe what you think the puppies from such a mating would look like.

• Explain what you believe would happen if you tried to mate a dog with a cat?

And you can only breed between organisms that are closely related – dogs with dogs, not dogs with cats. The same is true with plants. One apple variety can be crossed with another apple variety, but not with a tomato. With genetic engineering, it is possible to cut out a single gene from the genome of one organism, like a tomato, and paste it back into a tomato or into the genome of another organism, like an apple. This process is called recombinant DNA because it involves chemically recombining DNA.

• Describe why you think it is possible to move a gene from a tomato into an apple.

• Explain why you think moving a single gene from a tomato into apple would or would not make the apple red and seedy like a tomato.