Selective Breeding Genetics & Heredity

Selective Breeding Open up your classwork notebooks –Title: Selective Breeding –Date: 10/19/2015

Objectives for today 1. Define selective breeeding 2. Differentiate between the types of selective breeding. 3. Define inbreeding, cloning, genetic engineering, and hybridization.

Warm-Up When we created our children (either SpongeBob of Sesame Street genetics), were you able to select which male gamete fertilized the female gamete? Why or why not? Is it possible for parents to select which male gamete will fertilize which female gamete/

Warm-Up Activity Take the next few minutes to think about what selective breeding means. When you think you have a definition for selective breeding write it down in your notebook. After your definition write down a few examples of selective breeding.

Definition Selective Breeding- the process of selecting organisms with desired traits to be parents of the next generation. This definition is rather technical so let’s come up with a definition that is more user-friendly.

Examples of Selective Breeding What are some of the examples of selective breeding that you were able to come up with? As we go over these examples make sure to write them down in your notebooks.

Examples of Selective Breeding Images from: google.com

Types of Selective Breeding For example: A farmer might cross a male and female turkey that are both plump and grow quickly. Why would a farmer choose to cross these two turkeys? What could be the down side of crossing these two birds, if they are genetically similar?

Types of Selective Breeding Cloning- creating organisms that have exactly the same genes as the organism from which it was produced. What is an example of cloning that’s occurred in the past 20 years?

Dolly the Sheep In 1996, a group of scientists were able to clone a sheep. The resulting cloned sheep was named Dolly. Dolly was remarkable because she was the first mammal to be succesfully cloned.

How they cloned Dolly Image from

Issues with Dolly Dolly was able to produce 5 offspring in her lifetime. However, in 2001 Dolly developed arthritis. This onset of arthritis was early for a normal sheep. In 2003, Dolly was euthanized because of her arthritis and a progressive lung disease. Dolly’s breed of sheep typically live up to years old, where Dolly only lived to be 6 years old. Scientists are unsure if Dolly developed these symptoms because she was a clone or due to some other factor.

Issues with Cloning What could be some possible issues with cloning, scientifically speaking? Think of Dolly’s early onset of arthritis. Cloning is common occurrence in plants and bacteria. Image from starwars.wikia.com

Types of Selective Breeding Genetic Engineering- genes from one organism are transferred into the DNA of another organism. This technique is used to help produce medicines and improve food crops. Example: scientists have been able to insert genes into tomato and rice plants that enable the plants to survive in cold temperatures or poor soils. What could be the benefit for genetic engineering, in the case of the plants?

Genetic Engineering Genetic engineering is on the forefront for medical treatments. Doctors have used the practice of gene therapy, inserting copies of a gene directly into a person’s cells, to treat diseases. For example, doctors could be able to treat hemophilia by replacing the defective allele on the X-chromosome.

Issues with Genetic Engineering People are concerned with the long term effects of genetic engineering. They fear that genetically engineered crops might not be safe, they may cause harm to the environment or cause health issues in humans. How would scientists be able to adress these concerns?

Types of Selective Breeding Hybridization- the crossing of two genetically different individuals. A hybrid organism is formed to have the best traits from both parents. What is an example of hybridization that you have learned about in the past few years?

Extend your knowledge We have now covered four different forms of selective breeding. In your notebooks write a paragraph on whether or not you agree with selective breeding. Make sure to have at least 2 pros and cons supporting your reasoning. Make sure to use your genetics and heredity vocabulary terms.

Back to Hybridization The American Chestnut Project What is the main goal of the American Chestnut Foundation (ACF)? Image from gatacf.org

American Chestnut What caused a decline in American Chestnut trees? (There are multiple reasons) What two species of Chestnuts are being crossed? What are the desirable traits that the ACF are trying gain from both species of Chestnuts? What steps are currently being taken to help revive this tree species?

American Chestnut You will be given an exit ticket on the American Chestnut project. This sheet must be filled out before you can leave the classroom.