Traits and Heredity

Show the illustrations of the effect of sickle cell anemia on red blood cells. Ask students if they are familiar with the disease and how it is contracted.

Sickle cell is caused by genetics. It is not an infection or a cancer. It is important to differentiate people who have sickle cell anemia and those "with sickle cell trait."

The students portrayed in this reading are talking about genetic diseases, mostly about sickle cell anemia. They discuss how two recessive alleles result in this potentially fatal genetic disease. They discuss why these recessive alleles are more common in people from tropical regions and how inheriting one of these recessive alleles is actually helpful in combating malaria.

The passage ends with students discussing whether or not they should get a test to see if they are a carrier of this recessive allele.

The diagrams illustrate the role of genetics in producing carriers of this recessive allele and the likelihood of two carrier parents producing a child with the genetic disease.

​

Using the diagrams that are in the reading, carefully lead students through the the way that parents with and without the recessive allele can affect offspring. Ask students to talk through how the two situations diagrammed are different.

Make sure that students understand the difference between sickle cell anemia and sickle cell trait.

Introduce a topic for conversation or debate:

• Do you think people ought to find out whether or not they are carriers for genetic diseases before deciding to have children?
• Do you think people have a right to find out whether or not their partners are carriers for such diseases?

Also mention that many states already require that people be tested for certain diseases when they apply for a marriage license, but there is no required genetic testing in the U.S.

This will likely be a very difficult issue in the coming years as more information about genetic links to diseases becomes available.

Please carefully consider the experiences of your students and their families when making a decision about whether to use a debate format to engage with the topic. A class discussion can effectively replace the debate portion of this lesson.