2. Genetics The study of heredity, how traits are passed from parent to offspring x = or

3. The study of heredity started with the work of Gregor Mendel and his pea plant garden Mendel was an Austrian Monk that lived in the mid 1800’s

4.  What does it mean when pea plants are described as being true-breeding?. If the plants are allowed to self-pollinate, they would produce offspring identical to themselves

5.  https://www.youtube.com/watch?v=d4izVAk hMPQ https://www.youtube.com/watch?v=d4izVAk hMPQ

6.  Characteristic- a feature that has different forms in a population ◦ Hair color ◦ Eye color ◦ Height

7.  Characteristic- a feature that has different forms in a population ◦ Hair color ◦ Eye color ◦ Height

8.  Traits – variations of a characteristic ◦ Blonde hair ◦ Brown eyes ◦ tall

9.  Genes – a small section of a chromosome that carries the genetic code for a specific trait. A set of instructions for an inherited trait. ◦ Aa  Alleles - The different forms of a gene ◦ a

10. Gene

11. Homozygous Organisms that have two identical alleles for a particular trait (TT or tt) Heterozygous Organisms that have two different alleles for the same trait (Tt)

12. Phenotype ◦ Physical characteristic of an organism  Blonde hair  short Genotype ◦ Genetic makeup of an organism (Tt)

13.  Phenotype - the way an organism looks  red hair or brown hair  genotype - the gene combination of an organism  AA or Aa or aa

14.  Homo - Same  Hetero - Opposite  Pheno – Physical  Geno - Genetic

15. Hair color is a perfect example of a trait Prince Charming is blond Snow White has black hair What color hair should their children have?

16. There are two basic kinds of genes: ◦ Dominant - A gene that is always expressed and hides others ◦ Recessive - A gene that is only expressed when a dominant gene isn’t present

17. ◦ Letters are used as symbols to designate genes ◦ Capital letters are used for dominant genes ◦ Lower case letters are used for recessive genes ◦ Genes always exist in pairs

18.  A dominant gene will always mask a recessive gene.  A “widows peak” is dominant, not having a widows peak is recessive.  If one parent contributes a gene for a widows peak, and the other parent doesn’t, the off- spring will have a widows peak. Widows Peak

19. A Widows Peak, dominant, would be symbolized with a capital “W”, while no widows peak, recessive, would be symbolized with a lower case “w”. Father - No Widows Peak - w Mother - Has a Widows Peak - W

20. For the widows peak: WW - has a widows peak Homozygous dominant ww - no widows peak Homozygous recessive Ww - has a widows peak Heterozygous

21. Since Herman has no widows peak, he must be “ww”, since Lilly has a widows peak she could be either “WW” or “Ww” Definitely ww Homozygous recessive Ww or WW Heterozygous or Homozygous dominant

22. A “Punnet Square” is used to determine what pairs of genes A Punnet Square begins with a box 2 x 2 One parents pair is split into alleles on top, the other along the side Each allele is crossed with the other allele to predict the traits of the offspring

24. We can use a “Punnet Square” to determine what pairs of genes Lilly has Wwww Wwww w w Ww Assume Lilly is heterozygous Ww Herman is homozygous recessive ww

25. Notice that when Lilly is crossed with Herman, we would predict that half the offspring would be “Ww”, the other half would be “ww” Half “Ww”, Heterozygous, and will have a widows peak Half “ww”, Homozygous, and will not have a widows peak Wwww Wwww w w Ww

26. Another possibility is that Lilly might be “WW”, homozygous dominant. Ww w w WW Assume Lilly is homozygous dominant WW Herman is homozygous recessive ww Ww Notice that all the offspring are heterozygous and will have a widows peak

27. So which is true? Is Lilly homozygous dominant (WW) or is she heterozygous (Ww)? Ww w w WW ww Wwww w w Ww

28. Ww w w WW ww Wwww w w Ww If Lilly were heterozygous, then 1 / 2 of their offspring should have a widows peak, 1 / 2 shouldn’t If Lilly were homozygous, all of their children will have a widows peak

29. Recall that Herman and Lilly had another offspring, Marylin. She had no widows peak, therefore, Lilly must be heterozygous.

30. So, back to the original question. What color hair will the offspring of Prince Charming and Snow White have?

31. Hair color is different from widows peak, no color is truly dominant. ◦ Black and blond are the two, true traits ◦ Homozygous conditions produce either black or blond hair ◦ Heterozygous conditions produce brown hair

32. For Snow White to have brown hair she must be homozygous dominant, “BB”, a blond Prince Charming must be homozygous recessive, “bb”. Bb b b BB

33. All the offspring from Prince Charming and Snow White will therefore be heterozygous, “Bb”, and since hair color is an example of incomplete dominance….. all their children will have brown hair. +

34. Complete Dominance one trait is completely dominant over another trait. WW= widows peak Ww = widows peak ww = no widows peak

35. A Pedigree of a Dominant Human Trait

36. Note that the trait can appear in offspring of parents without the trait. Heterozygotes (hybrids) who do not show the trait are termed carriers. How many possible carriers are there on this pedigree? 7

37. Incomplete dominance Neither trait is dominant and the traits mix to form a third trait BB = Black hair Bb = Brown hair bb = blond hair

38. exceptions One thing Mendel didn’t realize was that there are some exceptions to the dominant / recessive pattern of inheritance that he observed in his pea plants. incomplete dominance.one allele/trait does not completely dominate the other allele/traitthe traits areblended One exception is: incomplete dominance. In this pattern, one allele/trait does not completely dominate the other allele/trait. The result: the traits are blended. F 1 generation: offspring of red and white flowers are all pink (a blend of the 2 parents’ colors). F 2 generation: offspring of pink plants are 25% red, 25% white, and 50% pink Incomplete Dominance Incomplete dominance

39. Here’s what’s happening: Redwhite pink Red crossed with white makes pink offspring. RR W W RWRWRWRW RW RW RW RW R W RR RW RW WW Pinkpink Pink crossed with pink makes: 25%red 25% red 25%white 25% white 50%pink 50% pink Incomplete Dominance

40.  A capital letter (P) represents one of the incompletely dominant alleles.  The same capital letter prime (P 1 ) represents the other incompletely dominant allele, so that the two do not get mixed up. curly hair (HH) In humans, curly hair (HH) straight hair (H 1 H 1 ). is incompletely dominant to straight hair (H 1 H 1 ). wavy hair (HH 1 ). A heterozygous human has wavy hair (HH 1 ). curly hair wavy hair Cross a person with curly hair with a person who has wavy hair. Incomplete Dominance

41. Both traits are dominant and you see both traits Blood Types A = dominant B = dominate O = recessive AO or AA = Type A BO or BB = Type B OO = Type O AB = A and B or AB

42. co-dominanceboth alleles both traits One exception to the dominant / recessive pattern is co-dominance. In this pattern, both alleles are dominant, and both traits are expressed. redwhite roanredwhite In cattle, red and white coats are co-dominant. The hybrid offspring is called roan; it has both red and white hairs in its coat. A capital letter represents one of the co-dominant alleles. A different capital letter represents the other co-dominant allele. RR red X WW white RW roan roan steer Co-Dominance

43. GG In horses, gray horses (GG) are codominant to white horses (WW). The heterozygous horse (GW) is an appaloosa horse (a white horse with gray spots). X White (WW) Appaloosa (GW) Co-Dominance Gray (GG)

44. ABABO  There are 4 blood types: A, B, AB, O A B  Blood type is determined by 2 factors in the blood: factors A and B. factor AType A If factor A is present, you are Type A. factor BType B If factor B is present, you are Type B. ABType AB If A and B factors are present, you are Type AB. neither factorType O. If neither factor is present, you are Type O. both The A and B factors are co-dominant; when both are present, both are expressed. Type O is recessive (needs two O genes to be present). BLOOD TYPE: an example of co-dominance in humans

45. PhenotypeGenotype Type A blood Type B blood Type AB blood Type O blood 1) What are the genotype and phenotype probabilities for the children of a man with Type A blood (homozygous) and a woman with type B blood (homozygous)? 2) What are the genotype and phenotype probabilities for the children of a man with Type O blood and a woman with Type AB blood? AA AAor AO BB BBor BO AB OO Blood Type Genotypes & Phenotypes

46. Type A blood (homozygous) Type B blood (homozygous)? 1) What are the genotype and phenotype probabilities for the children of a man with Type A blood (homozygous) and a woman with Type B blood (homozygous)? Type O bloodType AB blood 2) What are the genotype and phenotype probabilities for the children of a man with Type O blood and a woman with Type AB blood?

47. The likelihood that a particular event will occur is called: Probability

48. 1 out of 250%. Example A: If I flip a coin, the probability that it will show heads is 1 out of 2, or 50%. 1 out of 6 16.7% Example B: If I roll a die, the probability that I will roll a 3 is 1 out of 6, or 16.7%. Probability is calculated using this formula: Actual outcomes x 100 = Probability % Possible outcomes 3 out of 650% Example C: If I roll a die, the probability that I will roll an even number is 3 out of 6, or 50%.

49. What is the probability that a single coin flip will come up heads.  a. 100 percent  b. 75 percent  c. 50 percent  d. 25 percent

50.  Is the following sentence true or false? The past outcomes of coin flips greatly affect the outcomes of future coin flips.

51. A carrier is a person who does not have the recessive trait, but does have the recessive gene. (They’re hybrid) Exploring a Pedigree Pedigree: diagram that shows the presence of a trait in a family.

52. How many children did Victoria and Albert have? How many were daughters, and how many were sons? How many of Victoria’s daughters were carriers of the hemophilia gene? How many of Victoria’s sons were hemophiliacs? How many of her grandsons were hemophiliacs? How many of her great-grandsons? Pedigree of Queen Victoria of England for the trait of hemophiliahemophilia

54. determined by more than one genepolygenic When a single trait is determined by more than one gene, we say that it is polygenic. blood type eye color Height is a polygenic trait Also: hair color Polygenic Inheritance

55. Eye color is determined by more than one gene brown greengrayblueThus eye color appears to vary on an almost continuous scale from brown to green to gray to blue Multiple Alleles melanin bluegreen Eye color is determined by three genes: one controls texture of the iris which refracts light to make blue, and a second which determines the amount of pigment, called melanin. When a small amount of melanin is present, blue or green eyes result, while brown & black eyes result from increasing amounts of melanin

56. brown, green blackredviolet polygenic). Eye colors can range from the most common color, brown, to the least common, green. Rare genetic specialties can even lead to unusual eye colors: black, red, and violet. Eye color is an inherited trait influenced by more than one gene (polygenic). Heterochromia (eyes that are different colors) Brown (B)blue (b) Brownblue Green / hazel (G)lighter color(g).Green lighter-color There are 3 genes that control eye color. One gene has Brown (B) and blue (b) alleles (Brown is dominant over blue). The 2nd gene also has 2 alleles: Green / hazel (G) and lighter color (g). Green is dominant over the lighter-color allele. Eye Color Calculator activityCalculator Eye Color Eye Color

57. Hair color Hair color is determined by more than one geneHair color is determined by more than one gene Thus hair color appears to vary on an almost continuous scale from black to brown to blond to redThus hair color appears to vary on an almost continuous scale from black to brown to blond to red The brown and black pigment is melaninThe brown and black pigment is melanin The red pigment is an iron- containing moleculeThe red pigment is an iron- containing molecule

58. Black hair Dark brown hair Brown hair Auburn hair Red hair Blonde hair Grey (gray) hair White hair It is thought that hair color is controlled by two genes. Brown (B)blonde (b). Non-red (N)red (n). One gene has 2 alleles: Brown (B) and blonde (b). The 2nd gene has 2 alleles: Non-red (N) and red (n). The combination of these two genes, plus environmental factors (and age), contributes to the many different shades of hair color in humans. Hair color

59. melanin, Skin color is determined by the amount and type of melanin, the pigment in the skin. Skin color is determined by 6 different genes, which accounts for the vast range of different skin colors in human beings. link Skin Color

60. The structure and an actual picture of a chromosome. Human chromosome set from a skin cell. Chromosomes are long strands of DNA, wrapped around proteins. Humans have 46 chromosomes in every cell. Genes are sections of chromosomes. Humans have 20,000 - 25,000 genes in every cell. Chromosomes, Genes and DNA

61. How scientists read chromosomes Note that 22 of the 23 pairs of chromosomes are the same size, and have the same banding patterns. The first 22 pairs of chromosomes are called “autosomal.” However, the 23 rd pair of chromosomes do not look alike at all. The 23 rd pair of chromosomes are called the “sex” chromosomes, or “X and Y” chromosomes. Make a karyotype Karyotype: a picture of all 46 of a person’s chromosomes, arranged in 23 pairs.karyotype

62. Chromosome 1 pair False-color photograph shows human chromosomes, with the Chromosome 1 pair highlighted in blue. Chromosome 1 contains nearly twice as many genes as the average chromosome and makes up eight percent of the human genetic code. It is packed with 3,141 genes and linked to 350 illnesses including cancer, Alzheimer’s, Parkinson’s disease, and a gene for a common form of cleft lip and palate. Human Chromosome 1

63. The 23rd pair of chromosomes in humans determines a person’s gender. A female has two X chromosomes; a male has 1 X and 1 Y chromosome. Female: XX Male: XY X chromosome is much larger than the Y chromosome. X and Y Chromosomes

64. A B Which of these karyotypes shows a male, and which shows a female?

65. X egg X Y girl boy Gender Determination

66. Down Syndrome, or Trisomy 21, occurs when a person has 3 copies of Chromosome 21, instead of the normal 2 copies. Other Genetic Abnormalities Down Syndrome

67. FrogPeas Goldfish Apple Onion Potato Rice Tomato Dog Horse Housefly Mosquito Mouse Chicken PlantsAnimals Human 78 26 94 66 46 12 6 40 78 34 14 16 48 24 Corn20 Click here to find out how many chromosomes other species have.here Who’s Got the Most Chromosomes?

68. GENES BY THE NUMBERS Even though all the cells in the body contain the exact same genes, the genes that are “turned on” in each cell vary depending on the cell’s function. These are the numbers of working genes in different parts of the body. Brain3195 White blood cell2164 Liver2091 Heart1195 Pancreas1094 Bone 904 Colon 879 Skeletal muscle 735 Kidney 712 Skin 629 Thyroid Gland 584 Eye 547 Small Intestine 297 Smooth muscle 127 Esophagus 76 Red blood cell 8

69. YOU !!! 25, 000 genes 46 chromosomes 3 billion base pairs 1 billion codons in one human cell there are… Number of people on Earth: 7 billion Number of people with exactly your DNA 6.5 feet of DNA ….1 Some Genetics Numbers