1. GENETICS 1850’S & 1860’S Austrian monk named Gregor Mendel experimented with peas Mendel’s Experimental Setup; 1. He identified several characteristics to investigate. [short / tall, green peas / yellow...] 2. He created pure-breeding strains for each characteristic....He did this by repeated self-pollination & selective breeding of the peas.

2. GENETICS Pea flower

3. GENETICS Pollen from the plant’s stamen is placed on the same plant’s pistil. Offspring that show the desired characteristic are kept, others are destroyed. Repeat many generations until all offspring show the desired characteristic SELF-POLLINATION & SELECTIVE BREEDING

4. GENETICS Once Mendel had pure-breeding strains he could start his experiment

5. MENDEL ’ S EXPERIMENT 1. He crossed one pure-breeding plant with a pure-breeding plant for a different form of that characteristic. This is the PARENTAL or P1 generation RESULT...All the offspring showed the characteristic of the same parent These offspring are the FIRST FILIAL or F1 generation

6. MENDEL ’ S EXPERIMENT 2. He crossed one F1 plant with itself [or another F1 plant.] RESULT...75% showed the characteristic of the F1 plants, 25 % showed the hidden characteristic. These offspring are the SECOND FILIAL or F2 generation

7. MENDEL ’ S EXPERIMENT Parental [P1] Generation Pure-Breeding Tall X Pure-Breeding Short

8. MENDEL ’ S EXPERIMENT Parental [P1] Generation Pure-Breeding Tall X Pure-Breeding Short

9. MENDEL ’ S EXPERIMENT Parental [P1] Generation Pure-Breeding Tall X Pure-Breeding Short First Filial [F1] Generation All Tall

10. MENDEL ’ S EXPERIMENT First Filial [F1] Generation All Tall

11. MENDEL ’ S EXPERIMENT First Filial [F1] Generation All Tall Second Filial [F2] Generation 75% Tall 25% Short

12. MENDEL ’ S CONCLUSIONS 1. Each organism has 2 factors for each trait. 2. Dominant factors are shown whenever present Recessive factors may be hidden.

13. MENDEL ’ S CONCLUSIONS 3. Each parent gives one factor for each trait to its offspring. 4. Factors are independent of one another.

14. MODERN GENETICS Gene – A space on a chromosome that contains information for a characteristic Allele - one set of instructions that can go in a gene

15. MODERN GENETICS Letters represent alleles. Dominant are capitals, Recessive are the lower case of the dominant letter Example-T=tall (dominant) t=short (recessive)

16. MODERN GENETICS Phenotype ~ the appearance of the organism Genotype ~ the genes an organism carries Homozygous ~ containing 2 of the same allele Example-TT=Homozygous dominant tt=Homozygous recessive

17. MODERN GENETICS Heterozygous ~ containing 2 different alleles Example-Tt=Heterozygous What would the phenotype be for this plant?

18. MENDEL ’ S EXPERIMENT WITH GENOTYPES Parental [P1] Generation Pure-Breeding Tall X Pure-Breeding Short First Filial [F1] Generation All Tall

19. MENDEL ’ S EXPERIMENT WITH GENOTYPES Parental [P1] Generation Pure-Breeding Tall X Pure-Breeding Short TT tt First Filial [F1] Generation All Tall

20. MENDEL ’ S EXPERIMENT WITH GENOTYPES Parental [P1] Generation Pure-Breeding Tall X Pure-Breeding Short TT tt Tt Tt Tt Tt First Filial [F1] Generation All Tall

21. MENDEL ’ S EXPERIMENT WITH GENOTYPES First Filial [F1] Generation All Tall Tt Tt Tt Tt Second Filial [F2] Generation 75% Tall 25% Short

22. First Filial [F1] Generation All Tall Tt Tt Tt Tt Tt tt TT Tt Second Filial [F2] Generation 75% Tall 25% Short MENDEL ’ S EXPERIMENT WITH GENOTYPES

23. THE PUNNETT SQUARE Example Cross Tt female with Tt male

24. THE PUNNETT SQUARE Crossing Tt female with Tt male 1. Put possible gametes Female can give across top T t

25. THE PUNNETT SQUARE Crossing Tt female with Tt male 2. Put possible gametes male can give down side T t

26. THE PUNNETT SQUARE Crossing Tt female with Tt male 2. Put possible gametes male can give down side T t T t

27. THE PUNNETT SQUARE Crossing Tt female with Tt male 3. Put resulting genotypes in each square T t T t

28. THE PUNNETT SQUARE Crossing Tt female with Tt male 3. Put resulting genotypes in each square T t T TT t

29. THE PUNNETT SQUARE Crossing Tt female with Tt male 3. Put resulting genotypes in each square T t T TT Tt t

30. THE PUNNETT SQUARE Crossing Tt female with Tt male 3. Put resulting genotypes in each square T t T TT Tt t Tt

31. THE PUNNETT SQUARE Crossing Tt female with Tt male 3. Put resulting genotypes in each square T t T TT Tt t Tt tt

32. THE PUNNETT SQUARE Crossing Tt female with Tt male 4. Put resulting phenotypes in each square T t T TT Tt t Tt tt

33. THE PUNNETT SQUARE Crossing Tt female with Tt male 4. Put resulting phenotypes in each square T t T TT Tt Tall t Tt tt

34. THE PUNNETT SQUARE Crossing Tt female with Tt male 4. Put resulting phenotypes in each square T t T TT Tt Tall Tall t Tt tt

35. THE PUNNETT SQUARE Crossing Tt female with Tt male 4. Put resulting phenotypes in each square T t T TT Tt Tall Tall t Tt tt Tall

36. THE PUNNETT SQUARE Crossing Tt female with Tt male 4. Put resulting phenotypes in each square T t T TT Tt Tall Tall t Tt tt Tall Short

37. THE PUNNETT SQUARE Crossing Tt female with Tt male T t T TT Tt Tall Tall t Tt tt Tall Short Each square represents a possible offspring. Each square has equal probability.

38. THE PUNNETT SQUARE Crossing Tt female with Tt male T t T TT Tt Tall Tall t Tt tt Tall Short Genotype Ratio 1: 2 : 1 TT : Tt : tt 25% : 50% : 25% TT : Tt : tt

39. THE PUNNETT SQUARE Crossing Tt female with Tt male T t T TT Tt Tall Tall t Tt tt Tall Short Phenotype Ratio 3 : 1 Tall:short 75% : 25% Tall:short

40. INCOMPLETE DOMINANCE and CODOMINANCE Sometimes heterozygous individuals show an intermediate phenotype - Incomplete Dominance heterozygous – mixed phenotype - Codominance Example - Snapdragon flower color Alleles -R (red) & W (white) RR - red WW - White RW - Pink

41. SEX DETERMINATION IN HUMANS Sex determination in humans Chromosome pair #23 are sex chromosomes X and Y Female Genotype is XX Male Genotype is XY

42. SEX LINKED GENES Genes on a sex chromosomes are sex linked Examples: Hemophilia, Red-green colorblindness, Male Pattern Baldness Sex Linked genes may follow strange patterns through a pedigree

43. SEX LINKED GENES Hemophilia- exists on X chromosome and is recessive. Can be designated X h Possible genotypes Xy -Normal Male XX -Normal Female X X h -Normal (carrier) Female X h Y -hemophiliac Male X h X h -hemophiliac Female A carrier has a Normal Phenotype but can pass on the allele for hemophilia

44. MULTIPLE ALLELES For many genes there are more than 2 alleles Human blood type is an example 3 alleles IaIa IbIb ioio

45. MULTIPLE ALLELES Genotypes I a I a I b I b I a I b I a i o I b i o i o i o Phenotypes Type A Blood Type B Blood Type AB Blood Type A Blood Type B Blood Type O Blood