Dominant and Recessive Traits

1. Dominant and Recessive Traits How traits are transmitted through heredity

2. Genetic Trait: Long Second Toe

3. Comparison of 2 Genetic Traits Most people have a second toe that is shorter than their big toe. However, some people (about 4%) have a long second toe. Is having a long second toe a dominant or a recessive trait?

4. Genetic Trait: Color Blindness

5. Comparison of 2 Genetic Traits Most people can see color. However, about 5,000 out of 10,000 men are color blind. Is being color blind a dominant or a recessive trait?

6. Albinos have a rare genetic mutation. 1 in 17,000 organisms is an albino. Is this a dominant or a recessive trait?

7. Answer Answer: It is recessive. If an animal receives the mutated genes for albinism and for normal coloring, it is more likely that the normal gene will be expressed.

8. Question • If 2 organisms reproduce and 1 of the organisms has the dominant trait, will their offspring have the dominant or the recessive trait? • If this albino owl (recessive trait) and this normally colored, camouflaged owl reproduced, would they have…. • An albino baby • A baby that has a mix of their traits • A normally colored baby

9. Question • If 2 organisms reproduce and 1 of the organisms has the dominant trait, will their offspring have the dominant or the recessive trait? • If a tall person and a short person reproduce, would their offspring be… • Tall • Medium height • Short

10. Misconception • A misconception is an incorrect idea. One misconception that people used to have about heredity was that offspring would have a ½ and ½ mix of parents’ traits. • One of the people who helped correct this misconception was named Gregor Mendel. • Watch a short video clip about Mendel’s discovery • Complete a short quiz about Mendel’s discovery

11. Mendel’s 1st and 2nd Generations Mendel crossed tall and short pea plants. In Mendel’s 1st generation, all of the pea plants were tall. In Mendel’s 2nd generation, ¾ of the pea plants were tall. In the next lesson, we’ll learn more about dominant and recessive traits and how they combine in offspring.

12. Question • If 2 organisms reproduce and 1 of the organisms has the dominant trait, will their offspring have the dominant or the recessive trait? • If this albino owl (recessive trait) and this normally colored, camouflaged owl reproduced, would they have…. • An albino baby • A baby that has a mix of their traits • A normally colored baby

13. Familiarize Yourself with a Simulation • Gregor Mendel’s flower shop is a simulation that will eventually help us use an invention called a Punnett Square to breed for desired traits. • Without knowing how to use a Punnett Square, you will not be able to complete the entire simulation. However, practicing with the simulation will help you do it faster next week after we study the Punnett Square.