1. Foothill High School Science Department Introduction To Genetics The Work of Gregor Mendel

2. Foothill High School Science Department Gregor Mendel Born 1822Born 1822 AustriaAustria Studied University of ViennaStudied University of Vienna Spent 14 yrs. Teaching High School, Monastery & Studying Pea’sSpent 14 yrs. Teaching High School, Monastery & Studying Pea’s

3. Foothill High School Science Department Gregor Mendel InheritanceInheritance –Characteristics Passed From Parents To Offspring GeneticsGenetics –The Study of Heredity and Its Impact on Biology

4. Foothill High School Science Department Gregor Mendel’s Peas Studied Trait Transfer Between Stocks Of Garden Peas

5. Foothill High School Science Department Gregor Mendel’s Peas

6. Foothill High School Science Department Gregor Mendel’s Peas Mendel Succeeded Because His Pea Plants Were:Mendel Succeeded Because His Pea Plants Were: –True-Breeding Populations Were Available Produce Offspring Identical To ThemselvesProduce Offspring Identical To Themselves –Easily Visualized Characteristics –Reproduce Sexually –Pollination Could Be Controlled –They Have A Short Life Cycle –They Produce A Large Number of Offspring

7. Foothill High School Science Department Gregor Mendel’s Peas Cross Pollinating PeasCross Pollinating Peas –Instead of Self Pollination, The Pollen From One Plant Is Used To Pollinate The Egg Cells of Another Plant. –Cut Away Anthers –Hand Pollinated Using Pollen From A Chosen Plant

8. Foothill High School Science Department Pollination Process

9. Foothill High School Science Department Pollination Process

10. Foothill High School Science Department Genes & Dominance Trait –Specific Characteristic That Varies From One Individual To The Next: –Seed Color, Shape, Coat Color, Pod Shape, Color, Flower Position, Height

11. Genes & Dominance PParents F Filial (Offspring) F1F1F1F1 First Generation F2F2F2F2 Second Generation

12. Foothill High School Science Department Genes & Dominance Hybrid = Offspring of Crosses Between Parents With Different Traits. Alleles = Different Forms Of A Specific Gene (different forms of a Trait )

13. Foothill High School Science Department Genes & Dominance Mendel Expected Blended Offspring. (Tall + Short = Medium) That Did NOT Happen. All Offspring Displayed A Single Characteristic From One Of The Parents.All Offspring Displayed A Single Characteristic From One Of The Parents.

14. Foothill High School Science Department Mendel’s Proof F 1 Generation (1 st Generation) –One of the Alleles Disappeared (short) –Where did it go? –Was it destroyed? F 1 Generation – All Plants Were TALL P F1F1F1F1

15. Foothill High School Science Department Mendel's Proof Mendel Performed An F 1 Cross You cross pollinate two plants from the F 1 GenerationYou cross pollinate two plants from the F 1 Generation

16. Foothill High School Science Department Mendel's Proof The missing allele re-appears in the F 2 Generation

17. Foothill High School Science Department Mendel’s Proof

18. Foothill High School Science Department Genes & Dominance Mendel’s Hypothesis 1.Biological Inheritance Is Determined By Factors That Are Passed To The Next GenerationIs Determined By Factors That Are Passed To The Next Generation 2.Principle Of Dominance Some Alleles Are Dominant And Some Are Recessive.Some Alleles Are Dominant And Some Are Recessive.

19. Foothill High School Science Department Mendel’s Proof Key Concept Key Concept : When Each F 1 Plant Flowers, –The Two Alleles Are Segregated From Each Other So That The Gamete Carries Only A Single Copy Of Each Gene. –Therefore, each F 1 plant produces two types of gametes – one Tall and one Short.

20. Foothill High School Science Department Segregation Segregation: Separation of Alleles During Gamete Formation Remember: There are two copies (alleles) of each gene in each cell. One came from Mom, the other from Dad! The same is true in peas!

21. Foothill High School Science Department Mendel’s Proof MOMDAD F 1 Generation Egg 1 Egg 2 Sperm 1 Sperm 2