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2. Gregor Mendel Genetics =the branch of biology that deals with heredity. A great deal of what we know about genetics began with the work of a monk named G GG Gregor Mendel, who experimented with sweet pea plants in the 1800s. 2

3. Mendel’s Work Mendel studied the patterns of inheritance in pea plants. He chose seven traits to follow. 3

4. Mendel needed to make sure he had plants that always gave the same offspring-called true breeding. He “self-pollinated” plants until he got seeds that always gave the same offspring.4

5.  He took a purple flower plant and crossed it with a white flower plant.  He called these the parent generation (P 1 generation)  What do you think the offspring (the F 1 generation) looked like? ALL PURPLE X Pollen 5

6. POLLEN SAY WHAT??????? F1F1 F2F2 6

7. Mendel concluded: 1.Something is being passed from parent to offspring. 2.Sometimes you can see “it” and sometimes you can’t. 3.If you can see “it”- “it” is dominant. 4.If “it’s” there and you can’t see “it”- it’s recessive. 7

8. 1.Dominant alleles are shown using a capital letter (R) 2.Recessive alleles are shown using a lower case letter (r) Examples: R=red r=pink RR - ? Rr - ? Each version is called an allele. 8

9. 9 Alleles are locted on genes on chromosomes.

10. Law of Dominance States that the dominant allele will prevent the recessive allele from being expressed. The recessive allele will only appear when it is paired with another recessive allele in the offspring. 10

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13. We have two copies of all of our chromosomes Why? 13

14. BOY OR GIRL? 14

15. What is a gene? A segment on the chromosome that codes for a protein.A segment on the chromosome that codes for a protein. People have two copies of each gene, one copy inherited from the mother and the other copy inherited from the father.People have two copies of each gene, one copy inherited from the mother and the other copy inherited from the father. There are many versions of each gene-allelesThere are many versions of each gene-alleles 15

16. If the two alleles in the pair are identical, then the condition called homozygous. If the 2 alleles are different, the condition is called heterozygous. The term “hybrid” is sometimes used to refer to heterozygous. 16

17. Genotype: the genes or alleles (RR, Rr, rr) Phenotype: an organisms physical appearance (Red, White) 17

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19. 19 How did you end up with the traits and genes that you got? During meiosis, each egg or sperm only gets one copy of each chromosome.

20. Law of Segregation (separation) states that gene pairs separate when gametes (sex cells) are formed, so each gamete has only one allele of each gene pair. 20 AbAb aBaB AbAb aBaB AbAb aBaB AbAb aBaB AbAb aBaB

21. Law of Independent Assortment states that different pairs of genes separate independently of each other when gametes are formed.21 Example: Just because you get the gene for brown hair does not mean you will get the gene for blue eyes.

22. REVIEW 1. A trait is a characteristic an individual receives from its parents. 2. Genes carry the instructions responsible for the expression of traits. 3. A pair of inherited genes controls a trait. 4. One member of the pair comes from each parent. 5. Alternative versions of genes are known as alleles. 22

23. REVIEW Mendel’s Principles of Inheritance Inherited traits are transmitted by genes which occur in alternate forms called alleles 1.Principle of Dominance - when 2 forms of the same gene are present the dominant allele is expressed 2.Principle of Segregation - in meiosis two alleles separate so that each gamete receives only one form of the gene 3.Principle of Independent Assortment - each trait is inherited independent of other traits (chance) 23

24. Punnett Squares Used to determine the probability of a combination of alleles Example: If a heterozygous black rabbit is crossed with a heterozygous black rabbit, what are the chances the offspring will be black? 24

25. B=Black b= Brown Genotypes? Phenotypes? 25

26. Example EOCT Question: Earlobe shape is a human trait. Some people have free earlobes while others have attached earlobes. Two parents with free earlobes have four children. Three children have free earlobes and one child has attached earlobes. If these parents have another child, what is the probability that the child will have attached earlobes? A 25% B 50% C 75% D 100% 26

27. Example EOCT question: In humans, a widow’s peak is dominant over a continuous hairline. Mary’s father has a widow’s peak, but Mary and her mother have a continuous hairline. What is the genotype of Mary’s father? A HH B Hh C hh D cannot be determined 27

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29. blending Incomplete dominance - cross between organisms with two different phenotypes that produces offspring with a third phenotype that is a blending of the parental traits. Ex. Red and White = Pink 29

30. Incomplete Dominance 30

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32. Codominance a cross between organisms with two different phenotypes produces offspring with a third phenotype in which both of the parental traits appear together. Ex: Yellow and Orange = yellow with orange spots 32

33. Codominance Both phenotypes are expressed at the same time. Example: Blood Types GenotypePhenotype IOIOIOIO Type O IAIOIAIO Type A IAIAIAIA IBIOIBIO Type B IBIBIBIB IAIBIAIB Type AB There are 3 alleles for blood type- multiple alleles 33

34. W = allele for white flowers Codominance R = allele for red flowers W = allele for white flowers red x white ---> red & white spotted 34

35. Polygenic traits Most traits are controlled by many genes, not just one. Examples: hair color and skin color. There are several genes that control them. This is the reason that there are so many different colors of hair and skin in humans. 35

36. Sex Linked Traits Traits associated with particular sexes are called sex-linked or X-linked traits. These are usually carried on the X chromosome. Females = XX Males = XY 36

37. Karyotype 37 1 st 22 are Autosomes, the last pair (XY) are sex chromosomes)

38. Charts that show relationships within a family 38 Pedigree

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41. Autosomal- Dominant 41

42. SEX-LINKED 42

43. SEX-LINKED 43

44. Autosomal -Dominant 44

45. Genetic Disorders 45

46. Huntington’s Disease Huntington's disease degenerative disease that causes certain nerve cells in your brain to waste away. you may experience uncontrolled movements, emotional disturbances and mental deterioration. The disorder was documented in 1872 by American physician George Huntington. Fatal----ages:30-60 46

47. Colorblindness Sex-linked trait Gene for color vision located on the X chromosomes. MalesMales are more likely to have colorblindness because they have only one X chromosome 47

48. What do you see? The individual with normal color vision will see a 5 revealed in the dot pattern. An individual with Red/Green (the most common) color blindness will see a 2 revealed in the dots. What do you see? 48

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50. TEST50

51. Down Syndrome Three copies of chromosome #21. Symptoms: mental retardation and some physical deformities 51

52. Down’s Syndrome – How do you get 3 copies of chromosome 21? 52 Nondisjunction – failure of chromosomes to separate properly during cell division

53. Cystic Fibrosis caused by a recessive allele on chromosome #7. Deletion of three bases. Affects the body's respiratory and digestive systems. 53

54. Hemophilia  Sex-liked, recessive trait  Located on the X chromosome  Missing a protein necessary for blood clotting  Can bleed to death from minor cuts. 54

55. 55 Queen Victoria’s Pedigree showing Hemophelia

56. Sickle Cell People who carry the tendency to have sickle cell anemia are less likely to die from malaria.56

57. Gene Therapy 57 The insertion of healthy genes into an individual’s cells or tissues to treat a disease.

58. Example EOCT question: What is nondisjunction? A. failure of chromosomes to separate during meiosis B. failure of the cytoplasm to divide properly C. the insertion of a gene into a different chromosome D. the deletion of a gene from a chromosome 58

59. Which of the following shows how information is transformed to make a protein? A DNA  RNA  protein B gene  chromosome protein C cell respiration  ATP  protein D ATP  amino acid  protein 59

60. Information on mRNA is used to make a sequence of amino acids into a protein by which of the following processes? A replication B translation C transcription D transference 60

61. Pea plants have seeds that are either round or wrinkled. In this cross, what will be the phenotypic ratio of the offspring? A 50% RR and 50% Rr B 25% RR, 50% Rr, and 25% rr C 50% round seeds and 50% wrinkled seeds D 100% round seeds 61

62. What is a source of genetic variation? A mutation B adaptation C replication D transcription 62

63. A homozygous trait B dominant trait C recessive trait D heterozygous trait In Mendel’s experiments with a single trait, the trait that disappeared in the first generation and reappeared in the next generation is called the 63