1. The Work of Gregor Mendel

3. I) Historical Views A)Blending Theory A)Mixture of sperm & egg resulted in progeny that were a "blend" of two parents' characteristics B)Ignored characteristics that skipped generations-FLAW

5. II) Gregor Mendel “Father of Modern Genetics” A)His ideas form the backbone of modern genetics B)Most pea plants self-pollinate

6. II) Gregor Mendel C)He started with true-breeding pea plants 1) If allowed to self- pollinate, they produce identical offspring to parent

7. II) Gregor Mendel D)Cross-Pollinated plants for experiment E)He studied 7 different traits 1)A specific characteristic, such as seed color or height

8. Seed Shape Flower Position Seed Coat Color Seed Color Pod Color Plant Height Pod Shape Round Wrinkled Round Yellow Green Gray White Smooth Constricted Green Yellow Axial Terminal Tall Short YellowGraySmoothGreen Axial Tall The 7 traits Mendel studied

9. II) Gregor Mendel F)Called each starting plant the parent (P) G)Crossed plants with differing traits, resulting in offspring (F 1 ) 1)F 1 crosses between parents of different traits were hybrids

10. P Generation TallShortTall Short Principles of Dominance Go to Section:

11. P Generation F 1 Generation TallShortTall Short Principles of Dominance Go to Section:

12. Seed Shape Flower Position Seed Coat Color Seed Color Pod Color Plant Height Pod Shape Round Wrinkled Round Yellow Green Gray White Smooth Constricted Green Yellow Axial Terminal Tall Short YellowGraySmoothGreen Axial Tall The 7 traits Mendel studied

13. III) Mendel’s Conclusions A)Inheritance is determined by factors that are passed from one generation to the next 1)Today these factors are called genes 2)Alleles: Different forms of a gene B)Principle of Dominance 1)Some alleles are dominant, and others are recessive 2)Need only one dominant allele to see that trait (TT or Tt both tall) 3)Must lack any dominant alleles to see the recessive trait (only tt is short)

14. IV) Principle of Segregation A)What happened to the recessive traits? B)Mendel cross- fertilized the F 1 plants, resulting in F 2 offspring with some recessive alleles reappearing

15. IV) Principle of Segregation C)Alleles for a gene are segregated from each other during the formation of gametes

16. P Generation F 1 Generation TallShortTall Short Principles of Dominance & Segregation Go to Section:

17. P Generation F 1 Generation F 2 Generation TallShortTall Short Section 11-1 Mendel Observed the Principles of Dominance & Segregation Go to Section:

18. V) Probability A)The likelihood that a particular even will occur B)Can be used to predict the outcome of a particular genetic cross C)Used to predict averages, not precise numbers D)Use a tool called a Punnett Square

19. Punnet Squares: Why did Mendel obsereve what he did? COPY THIS

21. Notice all of the results are around a 3:1 ratio

22. VI) Genetics Key Terms A)Homozygous - when the two alleles are the same. B)Heterozygous - when the two alleles are different, in such cases the dominant allele is expressed

23. V) Genetics Key Terms C)Genotype- genetic make-up. D)Heterozygous – physical characteristics