1. CHAPTER 11 INTRODCUTION TO GENETICS

2. Grandfather Grandmother Father Mother ?

3. Genetics = A branch of Biology that studies Heredity 1800’s

4. Gregor Mendel = Father of Genetics Garden Pea Plant 1857

5. Sexual Reproduction Pea plants are available in many varieties with distinct heritable features (characters) with different variants (traits). Male Gamete = Pollen Female Gamete = Egg (stamens) (pistil/carpal)

6. Controlled fertilization Artificial cross-pollination (hybridize) Pollen

7. Monohybrid Cross = One Trait “Height” “True Breeding” = Homozygous Tall Pea x Short Pea TT x tt T = Dominant t = Recessive X “Homozygous Dominant” “Homozygous Recessive”

8. Generations P1 = Parent Plants -True breed Tall x True breed Short = First Generation (children) F1 100% TT x tt Genotype = Tt (Heterozygous) 4:4 100% Phenotype = Tall 4:4 100%

9. = Second Generation (grandchildren) Tt x Tt Genotype: 1 TT (Homozygous Dominant) 1:4 25% 2 Tt (Heterozygous) 2:4 50% 1 tt (Homozygous Recessive) 1:4 25% Phenotype Tall 3:4 (75%) Short 1:4 (25%) F2 75% 25%

10. Gene = a segment of DNA located on the chromosomes Alleles = different gene forms (tall or short) DadMom Diploid = 2n  Locus Tall or Short

11. 2 alleles determine a Trait: What happened in the F1? Mother’s + Father’s = Trait 

12. Dominant = Trait Observed Recessive = Trait that disappeared Tall = Dominant (T) Short = Recessive (t) Alleles: TT = Tall Tt = Tall tt = Short PhenotypeGenotype Can’t always know an organisms genotype by looking at its phenotype?

13. TT tt T t TtTt Homozygous Dominant Homozygous Recessive Heterozygous

14. Tt x Tt 3 Tall and 1 Short T t F1 F2 TtTt Combination of Letters/Alleles? TtTt Change of colors to follow the parental alleles:

15. Similar 3 to 1 ratios among F2 offspring when crossed for other traits

16. 1 st LAW OF HEREDITY “Law of Segregation” = –The 2 alleles for each trait must separate when gametes (sperm/egg) are formed. -A parent passes on, at random, only one allele for each trait to each offspring A  a

17. Segregation Random Fertilization

18. Law of Probability “Rules of Chance” “Odds” 20:1 5% 10:1 10% 2:1 50% Numerator = winner Denominator = # horses 1/12 1:12 “odd” 8% “chance”

19. Probability? “Chance” of getting a tail? “Chance” of getting snake eyes on two dice?

20. Male: Female XYXX ½ 1:2 odd Boy 1:2 odd Girl 50% chance Survey Large Number 1:1 “Chance” of getting a boy?

21. Punnett Square = used to predict and compare the genetic variations that will result from a cross If you know the genotypes of Parents, you can use a PS to predict the genotypes/ phenotypes of Offspring

22. Monohybrid Cross = Cross for one trait Genotype = PP (1:4) 25% Pp (2:4) 50% pp (1:4) 25% Phenotype = Purple (3:4) 75% White (1:4) 25% P P PP p pp p P P p p

23. 1.Make the square/ squares 2.Place the parents genotype (letters) on outside of square. 3.Fill in the individual squares 4.Ratio/ Percentage of Genotype (letters) 5.Ratio/ Percentage of Phenotype (look-like) Punnett Square Rules:

24. Dihybrid Crosses: Crossing for 2 characteristics/ traits

25. Seed Shape and Seed Color Shape =Round was Dominant to Wrinkled Color = Yellow was Dominant to Green

26. Round Yellow SeedsWrinkled Green Seeds RRYYrryy x F1 = All plants Round Yellow Seeds RRYYrryyRRYYrryy RrYy F1?

27. RrYy F2?

28. RrYy Round Yellow Round GreenWrinkled Yellow Wrinkled Green

30. RrYy RY Ry rY ry The two pairs of alleles segregate independently of each other. The presence of one specific allele for one trait has no impact on the presence of a specific allele for the second trait. Four classes of gametes (RY, Ry, rY, and ry) would be produced in equal amounts.

31. 2 ND LAW OF HEREDITY Law of Independent Assortment = genes for different traits are inherited “independently” of each other. RrYy = the R and r will separate as well as the Y and y. Alleles can recombine in 4 different ways.

32. HUMAN PHENOTYPES COMPLETE DOMINANCE

33. Cleft = Dominant Widow’s Peak = Dominant Clockwise = Dominant Dimples = Dominant

34. Bent Little Finger = Dominant Left Crossing Right = Dominant Mid-Digital Hair = Dominant Right Handed = Dominant Hitchhiker Thumb = Recessive

35. Free = Dominant Roll Tongue = Dominant Right Leg on Top = Dominant Shorter Big Toe = Dominant PTC Taste = Dominant

36. PATTERNS OF HEREDITY EXTENDING MENDELIAN GENETICS

37. Flower color of snapdragons INCOMPLETE DOMINANCE Heterozygote

38. Shorthorn Red Shorthorn White Recessive Shorthorn Roan CODOMINANCE Two alleles affect the phenotype in separate, distinguishable ways. Dominant alleles do not somehow subdue a recessive allele

39. MULTIPLE ALLELES

41. HUMAN BLOOD TYPES Three alleles: I A, I B, and i Which dominant? Codominant? place type A oligosaccharides on the surface of their red blood cells Type? B AB Neither 4 6 A and B are completely dominant over i A and B

42. Antibodies present in blood = proteins If the donor’s blood has an A or B factor that is foreign to the recipient, antibodies in the recipient’s blood will bind to the foreign molecules, cause the donated blood cells to clump together, and can kill the recipient. Universal donor? Universal recipient?OAB

43. Sub-Saharan African Indian Southern European Northern European Quantitative Characters = an either-or classification is impossible Characters vary in the population along a continuum (in gradations) Polygenic Inheritance More than one gene determines the trait

44. Skin pigmentation (A, B, C) AABBCC = very dark aabbcc = very light “Bell Curve/ Normal Distribution” At least 3 genes involved A dominant over a B dominant over b C dominant over c AaBbCc = intermediate

45. Environmental Factors = Cool 30 o C = Female Warm 34 o C = Male

46. Environmental Influences = Age

47. Check Fetus for Genetic Disorders

48. When you contemplate all that can occur in the pathway from genotype to phenotype = His work was “impressive” indeed

49. Pedigree Studying humans: 1 generation = ~20 years Few offspring Not moral to study = “Family Tree” Follow certain traits through family histories Understand past and predict the future MENDELIAN INHERITANCE IN HUMANS

50. YouTube - I'm My Own Grandpa

51. YouTube - I'm My Own Grandpa- Ray Stevens ( with family tree diagram)