2. Basic Genetics Gregor Mendel The Father of Genetics

3. Gregor Mendel

4. Objectives: To distinguish between heredity and inheritance To distinguish between heredity and inheritance To define pollination To define pollination To identify the major parts of a flowering plant To identify the major parts of a flowering plant To describe Mendel’s experiments in heredity To describe Mendel’s experiments in heredity

5. Heredity – transmission of traits from parents to their offspring Inheritance passing of traits by heredity

6. Mendel’s experiments used pea plants

7. Pollination – transfer of pollen from anthers to stigma in flowers 1) self pollination occurs within the same flower or same plant 2) cross pollination occurs between different plants

8. Receptical

10. Mendel’s Crosses with Pea Plants Pure tall plants X Pure short plants P1P1 parental generation Cross Pollination All Tall plants F1F1 first filial generation Self Pollination 787 tall plants, 277 short plants F2F2 second filial generation 3 to 1 ratio

12. Objective: To describe Mendel’s 3 principles of inheritance To describe Mendel’s 3 principles of inheritance

13. 1) Principle of Dominance and Recessiveness Each trait is controlled by 2 factors, one factor (dominant ) may mask the other factor (recessive ) preventing it from having an effect. P1P1 F1F1 F2F2

14. 2) Principle of Segregation The two factors for a characteristic separate during the formation of eggs and sperm. The two factors for a characteristic separate during the formation of eggs and sperm.

15. 3) Principle of Independent Assortment Factors for different characteristics are distributed to reproductive cells independently. Factors for different characteristics are distributed to reproductive cells independently.

16. Objectives: To define gene To define gene To define allele To define allele

17. Gene – segment of DNA on a chromosome that codes for a particular protein genes occur in pairs genes occur in pairs

18. Allele – alternative form of a gene g = yellow pods G = green pods t = short T = tall Dominant capital letter Recessive Lowercase letter

19. Objectives: To define genotype and phenotype To define genotype and phenotype To distinguish between homozygous and heterozygous To distinguish between homozygous and heterozygous To define multiple alleles To define multiple alleles

20. Genotype – genetic makeup of an organism (genes) (internal information)

21. (external appearance) Phenotype – physical characteristics of an organism

22. What does Phenotypes come form

23. Example of Genotype and Phenotype TT genotype Tall phenotype

24. Homozygous – when both alleles of a pair are the same homozygous dominant homozygous recessive TT tt

25. Heterozygous – when both alleles of a pair are not the same heterozygous (tall) Tt

26. Multiple alleles – 3 or more alleles that control a trait Example – blood type (I A,I B,i o ) Example – blood type (I A,I B,i o ) GENOTYPES I A I A I A i o RESULTING PHENOTYPES Type A Type A IBIBIBioIBIBIBioIBIBIBioIBIBIBio Type B Type B IAIBIAIBIAIBIAIB Type AB ioioioioioioioio Type O

27. Objectives: To define probability To define probability To predict the results of monohybrid crosses by using a Punnett square To predict the results of monohybrid crosses by using a Punnett square

28. Probability = number of times a particular event occurs number of opportunities for the event to occur Probability – likelihood that a particular event will occur

29. Example 1: Flipping a Coin Chances of coming up heads = ½

30. Example 2: Rolling Dice 1 6 x 1 6 = 1 36 probability of rolling a six on 1 dice probability of rolling a six on 1 dice probability of rolling a six on 2 dice

31. monohybrid cross –

32. Objectives: To define test cross To define test cross To define incomplete dominance To define incomplete dominance To define codominance To define codominance

33. Test cross – an individual with unknown genotype is crossed with a homozygous recessive individual used to determine the genotype of any individual whose phenotype is dominant used to determine the genotype of any individual whose phenotype is dominant

34. In rabbits, black fur color is dominant over brown fur color B = black fur b = brown fur bb BBorBb

35. Incomplete Dominance when 2 or more alleles influence the phenotype when 2 or more alleles influence the phenotype results in a trait intermediate between the dominant and recessive traits

36. Incomplete Dominance

37. Codominance – condition in which both alleles of a gene are expressed example – roan coat in horses example – roan coat in horses white hair (H W ) is codominant with red hair (H R ) white hair (H W ) is codominant with red hair (H R ) horses with genotype (H R H W ) have coats with a mixture of red and white hairs (roan) horses with genotype (H R H W ) have coats with a mixture of red and white hairs (roan)

38. Roan Coat

39. Objectives: To predict the results of dihybrid crosses by using a Punnett square To predict the results of dihybrid crosses by using a Punnett square

40. dihybrid cross – cross between individuals that involves two pair of contrasting traits