1 Mendelian Inheritance... the outward physical manifestation of internally coded, inheritable, information.

2 Genetics vs Heredity? Genetics: the branch of biology that studies heredity Heredity: the passing of characteristics (or traits) from parents to offspring

3 Gregor Mendel Father of Genetics Monk in Austria/Czech Republic Experimented with garden peas

4 Mendel…Why do you think? His experiments were successful? He used peas? He controlled his experiments? How did he do it? Why would his profession be beneficial?

5 Short Tall

6 Mendel’s Hypotheses Each parent has two factors (alleles) Each parent gives one of those factors to the offspring Tall has TT Short has tt Tall is dominant Short is recessive

7 TTtt T t Tt

8 TT T T

9 tt t t

10 A Monohybrid cross.. What’s the answer? The original parents differ by what? The original parents are called the? Their offspring are called what (the kids)? And their offspring are called what (the grandkids)?

11 Discovery of Chromosomes in 1900 Confirms Law of Segregation Chromosomes are in pairs Each chromosome has one of the allele pairs for each trait

12 Homologous Chromosomes Chromosomes of the same pair Each homologue will have one allele for a paired gene Homologous chromosomes pair up during meiosis Only one of each homologue will be in each gamete

13 Chromosomes line up in a double row. Meiosis Metaphase Assume a T allele on each red chromatid and a t allele on each blue chromatid TTtt

14 Chromosomes separate Each each daughter cell gets doubled chromosomes TT tt

15 Doubled Chromosomes Separate in Second Meiotic Division TT tt

16 Each gamete will have a T allele or a t allele TTtt

17 Allele Member of a paired gene –One allele comes from each parent Represented by a single letter

18 Mendel’s Law of Dominance Dominant alleles are expressed Recessive alleles are not expressed in the presence of a dominant allele –Recessive alleles are only expressed if both alleles are present

19 Gene A unit of heredity that controls the development of one trait Made of DNA Most genes are composed of two alleles My genes are Tommy genes!

20 Keeping Up Quick Check: What is the relationship between DNA & genes & homologs ^ homolgous chromosomes? Can you draw a picture?

21 Homozygous Both alleles alike AA or aa A A a a

22 Heterozygous Alleles are different Aa

23 Law of Segregation Mendel’s Gametes have 1 allele for each trait 2 alleles for each trait separate during meiosis During fertilization, the alleles for that trait reunite. This happens at random to create individuals of the next generation.

24 Genotype Genetic make up Represented by alleles TT & Tt are genotypes for tall pea plants This is the "internally coded, inheritable information" carried by all living organisms.

25 Phenotype The characteristic Genotype determines the phenotype Tall is a phenotype “Think adjective!” Descriptive This is the "outward, physical manifestation" of the organism.

26 A flower…. Phenotype: red flowers Cells contain red granules & enzymes help convert colorless pigment into red pigment Most enzymes are proteins Most traits are produced by the action of proteins.

27 Sickle Cell Anemia RBCs sickle shaped Anemia Pain Stroke Leg ulcers Jaundice Gall stones Spleen, kidney & lungs

28 Sickle Cell Anemia Recessive allele, s codes for hemoglobin S –Long rod-like molecules –Stretches RBC into sickle shape Homozygous recessive, ss have sickle cell anemia Heterozygous, Ss are carriers

29 Albinism Lack of pigment –Skin –Hair –Eyes

30 Amino AcidsMelanin Pigment Enzyme A a AA = Normal pigmentation Aa = Normal pigmentation aa = Albino

31 PKU Disease Phenylalanine excess Mental retardation if untreated Molly’s Story

32 PhenylalanineTyrosine Enzyme P p PP = Normal Pp = Normal pp = PKU

33 A man & woman are both carriers (heterozygous) for albinism. What is the chance their children will inherit albinism?

34 AA = Normal pigmentation Aa = Normal pigmentation (carrier) aa = Albino Man = AaWoman = Aa A a a A

35 A a a A AA Aa aa

36 AA Aa aa Genotypes 1 AA, 2Aa, 1aa Phenotypes 3 Normal 1 Abino Probability 25% for albinism

37 A man & woman are both carriers (heterozygous) for PKU disease. What is the chance their children will inherit PKU disease?

38 p p P PP PpPp PpPp pp P PP = Normal Pp = Normal (carrier) pp = PKU disease

39 PP Pp pp Genotypes 1 PP, 2Pp, 1pp Phenotypes 3 Normal 1 PKU disease Probability 25% for PKU disease

40 A man with sickle cell anemia marries a woman who is a carrier. What is the chance their children will inherit sickle cell anemia?

41 s s s Ss ss S SS = Normal Ss = Normal (carrier) ss = Sickle Cell

42 Ss ss Genotypes 2 Ss, 2ss Phenotypes 2 Normal (carriers) 2 Sickle cell Probability 50% for Sickle cell

43 Dwarfism = D Normal height = d DD = Dwarfism Dd = Dwarfism dd = Normal height Dwarfism Oddly a dominant trait Dwarf Band

44 A man with heterozygous dwarfism marries a woman who has normal height. What is the chance their children will inherit dwarfism? Dwarfism is dominant.

45 d d D Dd dd Dd dd d DD = Dwarf Dd = Dwarf dd = Normal

46 Dd dd Dd dd Genotypes 2 Dd, 2dd Phenotypes 2 Normal 2 Dwarfs Probability 50% for Dwarfism

47 Law of Independent Assortment The inheritance of one gene does not influence the inheritance of another gene if they are on separate chromosomes. The gene for albinism does not affect the gene for dwarfism The random distribution of alleles occurs gamete formation & genes on chromosomes sort independently during meiosis

48 A Dihybrid Cross A heterozygous tall plant that is also heterozygous for yellow seeds self pollinates. Tall and yellow seeds are dominant to short and green seeds. What are the genotypes & phenotypes of the offspring in fractions?

49 Tall Yellow TtYy TY What gametes can each parent produce? Ty tY ty TtYy TY Ty tY ty Tall Yellow

50 9 Tall-Yellow Match gametes on a Punnent Square TY Ty tY ty TYTytYty TtYy TTYYTTYyTtYY TTYyTTyyTtyy TtYYTtYyttYYttYy TtYyTtyyttYyttyy 3 Tall-Green 3 Short-Yellow 1 Short-Green

51 A man with blue eyes and normal height marries a woman with heterozygous brown eyes and homozygous dwarfism. What are the possible phenotypes of their children? Dwarfism & brown eyes are dominant. (Calculate in % & ratios)

52 Normal height-Blue ddbb db What gametes can each parent produce? DDBb DB Db DB Dwarf-Brown

53 The Answers: Dwarf-Brown eyes Dwarf-blue eyes Normal height-Brown eyes Normal height-Blue eyes

54 The End of Mendlian Genetics

55 Pedigree Shows relationships Used to determine inheritance patterns

56 Pedigree Symbols Female Male Person has a trait Parents Children Parents Parents closely related

57 Dominant Pedigree Affected individual must have a parent with the trait

58 Genotypes AA Aa aa Aa Could have either genotype

59 Recessive Pedigree May appear when neither parent has the trait If both parents have the trait, all the children will inherit it

60 Genotypes aa Aa AA Aa AA

61 Is this a dominant or recessive pedigree? Click for answer

62 Recessive pedigree Recessive because it appears in individuals when their parents do not have the trait.

63 Give genotypes for marked individuals Click for answer

64 Genotypes aa Aa AA or Aa

65 Is pedigree dominant or recessive? Click for answer

66 Dominant pedigree Dominant because all affected individuals inherited trait from a parent

67 Give genotypes for marked individuals Click for answer

68 Give genotypes for marked individuals Aa aa

69 The End