1. Gregor Mendel Genetics Experiments With Pea Plants

2. Mendel Noticed  Pea Plants varied by: height, color of flowers, position of flowers, seed color, seed shape, pod color, pod shape

3. Mendel Hypothesized

4.  Variations in pea plant appearance was due to something (some information) passed along during reproduction by the parent plants.

5. Mendel’s Experimental Design

6.  Mendel raised pea plants to “breed true,” I.e. tall only produced tall, short only produced short

7. Mendel’s Experimental Design  Mendel raised pea plants to “breed true,” I.e. tall only produced tall, short only produced short  Mendel crossed one true-breeding variety with the alternate true-breeding variety, e.g. tall x short

8. P 1 Tall X Short

9. F 1 All Tall

10. P 1 Tall X Short F 1 All Tall F 2 3/4 Tall 1/4 Short

11. Mendel Hypothesized  That something was passed from parents to offspring to determine height; he called this an allele

12. P 1 Tall X Short Tt F 1 All Tall T F 2 3/4 Tall 1/4 Short Tt

13. Mendel Hypothesized  That something was passed from parents to offspring to determine height; he called this an allele  Further, since the t allele was “hidden” in the F 1, but reappeared in the F 2, plants must have a pair of alleles for each trait.

14. P 1 Tall X Short TTtt F 1 All Tall Tt F 2 3/4 Tall 1/4 Short T?tt

15.  When an organism had a pair of alleles the same, e.g. TT or tt, he called this homozygous  When an organism had an unlike pair of alleles, e.g. Tt, he called this heterozygous  These terms refer to an organism’s genotype  The appearance of the organism he called it’s phenotype

16. Practice Vocab Ex. Plant Height Genotype Phenotype Pure or Hybrid Homozygous/ Heterozygous

17. More practice Genotype Phenotype Pure or Hybrid Homozygous/ Heterozygous Ex. Flower color

18. Mendel proposed several principles regarding his findings  If an organism is heterozygous and only one phenotype appears, this is the dominant phenotype, the alternate is the recessive phenotype  When an organism reproduces, allele pairs must segregate and only one member of each allele pair is passed along to the next generation.

19. Solving Genetic Problems T t TTt t T X t = T t F1

20. Punnett Square

21. TT X tt TTTT t t Tt Genotype 4/4- Tt Phenotype 4/4- Tall

22. Practice Space

23. Test Cross  What is the genotype of a short pea plant?______  What is the genotype of a tall pea plant?_____ or _____  Mendel developed a way of testing whether the tall plant is homozygous or heterozygous. It was the test cross

24. Test Cross problem T_ X tt

25. Independent Assortment  The inheritance of any characteristic is independent of the inheritance of any other characteristic. Ex. The inheritance of height is independent from pea color. Mendel provided evidence for this through dihybrid crosses.

26. Dihybrid Cross  TtPp X TtPp To solve this problem you can use a 16 block punnett square or the Forkline method.

27. 16 Block Punnett Square

28. Fork Line Method

29. Ex. TtPp X TtPp

30. Practice with Fork Line Method

31. Practicing Punnett Squares

32. Chromosome Options

35. Typical Dihybrid Cross RrYy x RrYy

36. Dihybrid Cross with Crossover  CcShsh x ccshsh

38. Random Assortment