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Genetics Heredity  Inheritance of traits Miller, K. R., & Levine, J. S. (2005). Chapter 11: Introduction to Genetics. Prentice Hall biology (North Carolina.

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Presentation on theme: "Genetics Heredity  Inheritance of traits Miller, K. R., & Levine, J. S. (2005). Chapter 11: Introduction to Genetics. Prentice Hall biology (North Carolina."— Presentation transcript:

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2 Genetics

3 Heredity  Inheritance of traits Miller, K. R., & Levine, J. S. (2005). Chapter 11: Introduction to Genetics. Prentice Hall biology (North Carolina ed., pp ). Upper Saddle River, N.J.: Prentice Hall.

4 Genetics Gregor Mendel  Suggested that paired factors, or genes, carry inherited traits.  Predicted how traits were inherited by studying pea plants Miller, K. R., & Levine, J. S. (2005). Chapter 11: Introduction to Genetics. Prentice Hall biology (North Carolina ed., pp ). Upper Saddle River, N.J.: Prentice Hall.

5 Simple Dominant Traits  Traits that are controlled by one pair of genes  One dominant allele is all that the organism needs to show the dominant trait Miller, K. R., & Levine, J. S. (2005). Chapter 11: Introduction to Genetics. Prentice Hall biology (North Carolina ed., pp ). Upper Saddle River, N.J.: Prentice Hall.

6 Tongue Roll Dominant trait Recessive attached ear lobes Dominant Free Ear Lobes Hitch hiker’s thumb Dominant Regular thumb Recessive

7 Section 10.1 Summary – pages Recessive trait Dominant trait Seed shape Seed color Flower color Flower position Pod color Pod shape Plant height round yellow purple axial (side) green inflated tall wrinkled green white terminal (tips) yellow constricted short Miller, K. R., & Levine, J. S. (2005). Chapter 11: Introduction to Genetics. Prentice Hall biology (North Carolina ed., pp ). Upper Saddle River, N.J.: Prentice Hall.

8 Alleles  Different forms of a gene type  Organisms have two genes (alleles) for each trait.  One gene (allele) from female gamete (egg).  One gene (allele) from male gamete (sperm). Miller, K. R., & Levine, J. S. (2005). Chapter 11: Introduction to Genetics. Prentice Hall biology (North Carolina ed., pp ). Upper Saddle River, N.J.: Prentice Hall.

9 Dominant gene (allele)  Stronger of two genes  Represented with capital letters  Written first  Example: T for tall plant height Miller, K. R., & Levine, J. S. (2005). Chapter 11: Introduction to Genetics. Prentice Hall biology (North Carolina ed., pp ). Upper Saddle River, N.J.: Prentice Hall.

10 Recessive gene (allele)  Weaker of two genes  Can be hidden by dominant genes.  Represented with lower case letters  Example: t for short plant height Miller, K. R., & Levine, J. S. (2005). Chapter 11: Introduction to Genetics. Prentice Hall biology (North Carolina ed., pp ). Upper Saddle River, N.J.: Prentice Hall.

11 Pure (Homozygous)  Two of the same genes (alleles) for a trait  Example: TT (homozygous dominant) or tt (homozygous recessive) Miller, K. R., & Levine, J. S. (2005). Chapter 11: Introduction to Genetics. Prentice Hall biology (North Carolina ed., pp ). Upper Saddle River, N.J.: Prentice Hall.

12 Hybrid (Heterozygous)  Two different alleles for a trait  Example: Tt Miller, K. R., & Levine, J. S. (2005). Chapter 11: Introduction to Genetics. Prentice Hall biology (North Carolina ed., pp ). Upper Saddle River, N.J.: Prentice Hall.

13 Genotype  Combination of alleles or genes for a certain trait  Example: Tt, TT, tt Miller, K. R., & Levine, J. S. (2005). Chapter 11: Introduction to Genetics. Prentice Hall biology (North Carolina ed., pp ). Upper Saddle River, N.J.: Prentice Hall.

14 Phenotype  Visible traits (how it looks)  Determined by looking at organism  Example: tall, short Miller, K. R., & Levine, J. S. (2005). Chapter 11: Introduction to Genetics. Prentice Hall biology (North Carolina ed., pp ). Upper Saddle River, N.J.: Prentice Hall.

15 Genotype or Phenotype? Tt Round Black BB Smooth rr Tall Miller, K. R., & Levine, J. S. (2005). Chapter 11: Introduction to Genetics. Prentice Hall biology (North Carolina ed., pp ). Upper Saddle River, N.J.: Prentice Hall.

16 In pea plants, green pods are completely dominant over yellow. What are the genotypes? Homozygous yellow Heterozygous green Pure dominant Hybrid gg GgGg GG GgGg Miller, K. R., & Levine, J. S. (2005). Chapter 11: Introduction to Genetics. Prentice Hall biology (North Carolina ed., pp ). Upper Saddle River, N.J.: Prentice Hall.

17 In pea plants, green pods are completely dominant over yellow. Pure yellow Homozygous recessive Pure green Heterozygous Yellow gg GgGg GG Miller, K. R., & Levine, J. S. (2005). Chapter 11: Introduction to Genetics. Prentice Hall biology (North Carolina ed., pp ). Upper Saddle River, N.J.: Prentice Hall.

18 In guinea pigs, short hair is dominant over long hair What letter should be used for the gene for hair length? What hair length will be represented by a capital S? What hair length will be represented by a lower case s? Miller, K. R., & Levine, J. S. (2005). Chapter 11: Introduction to Genetics. Prentice Hall biology (North Carolina ed., pp ). Upper Saddle River, N.J.: Prentice Hall.

19 What phenotypes would result from the following genotypes? SS ss Ss Miller, K. R., & Levine, J. S. (2005). Chapter 11: Introduction to Genetics. Prentice Hall biology (North Carolina ed., pp ). Upper Saddle River, N.J.: Prentice Hall.

20 TT T T tt t t Tall plant Short plant All tall plants What are the phenotypes of the parent plants? If both parents are pure, what are their genotypes? Which gene or allele can each parent pass on to the offspring? What is the phenotype of the offspring? What is the genotype of the offspring?

21 In pea plants, round pea pod texture is dominant over wrinkled texture. What is the genotype of the following? homozygous round heterozygous wrinkled pure dominant hybrid round Miller, K. R., & Levine, J. S. (2005). Chapter 11: Introduction to Genetics. Prentice Hall biology (North Carolina ed., pp ). Upper Saddle River, N.J.: Prentice Hall.

22 In pea plants, round pea pod texture is dominant over wrinkled texture. What is the genotype of the following? pure recessive heterozygous round pure wrinkled hybrid pure round Miller, K. R., & Levine, J. S. (2005). Chapter 11: Introduction to Genetics. Prentice Hall biology (North Carolina ed., pp ). Upper Saddle River, N.J.: Prentice Hall.

23 Punnett Squares  Punnett squares – used to predict and compare the genetic differences that will result from a cross. Miller, K. R., & Levine, J. S. (2005). Chapter 11: Introduction to Genetics. Prentice Hall biology (North Carolina ed., pp ). Upper Saddle River, N.J.: Prentice Hall.

24 Section 10.1 Summary – pages Monohybrid crosses Heterozygous tall parent Tt T t Tt T t Heterozygous tall parent TTTt tt Miller, K. R., & Levine, J. S. (2005). Chapter 11: Introduction to Genetics. Prentice Hall biology (North Carolina ed., pp ). Upper Saddle River, N.J.: Prentice Hall.

25 Generations of Inheritance Short pea plant Tall pea plant All tall pea plants 3 tall: 1 short P1P1 F1F1 F2F2 ttTT Tt TTTt tt Start by crossing homozygous parents Results in heterozygous offspring Crossing heterozygous offspring from F 1 generation results in three tall and 1 short

26 Incomplete dominance  Alleles BLEND (mix)  Neither gene is dominant  A third or new phenotype can be seen  Think about colors of paint Miller, K. R., & Levine, J. S. (2005). Chapter 11: Introduction to Genetics. Prentice Hall biology (North Carolina ed., pp ). Upper Saddle River, N.J.: Prentice Hall.

27  If a red impatient is crossed with a white impatient, the resulting flowers are pink.  Red and white blend like paint colors to produce pink (new phenotype). Red PINK X White Miller, K. R., & Levine, J. S. (2005). Chapter 11: Introduction to Genetics. Prentice Hall biology (North Carolina ed., pp ). Upper Saddle River, N.J.: Prentice Hall.

28 Incomplete Dominance R R W W RWRW RWRW RWRW RWRW

29 Codominance  Both alleles are dominant  Both alleles are seen (expressed) TOGETHER  There is NO “blending” Miller, K. R., & Levine, J. S. (2005). Chapter 11: Introduction to Genetics. Prentice Hall biology (North Carolina ed., pp ). Upper Saddle River, N.J.: Prentice Hall.

30 X WhiteRed Codominance Both alleles or genes are expressed Red & White Miller, K. R., & Levine, J. S. (2005). Chapter 11: Introduction to Genetics. Prentice Hall biology (North Carolina ed., pp ). Upper Saddle River, N.J.: Prentice Hall.

31  Red cow crossed with white cow results in roan cattle. Roan cattle have both red and white hairs. Codominance

32 Example: White chicken x black chicken = black and white checkered chicken

33 Incomplete or Codominance?  A white cow and a red cow produce a roan cow, one that has both white and red hairs.  A red flower and a white flower produce pink flowers.  A black cat and a tan cat produce tabby cats, cats where black and tan fur is seen together.

34 Incomplete or Codominance?  A blue blahblah bird and a white blahblah bird produce offspring that are silver.  A certain species of mouse with black fur is crossed with a mouse with white fur and all of the offspring have grey fur.  A woman with blood type A and a man with blood type B have a child with blood type AB.

35 Blood Types (codominant)  Blood type is codominant  4 different blood types Phenotype (Blood type) Genotype (Alleles or genes for blood type) A I A I A, I A i B I B I B, I B i AB IAIBIAIB Oii

36 Charles Drew  Charles Drew impacted blood donation and blood banks Miller, K. R., & Levine, J. S. (2005). Chapter 11: Introduction to Genetics. Prentice Hall biology (North Carolina ed., pp ). Upper Saddle River, N.J.: Prentice Hall.

37 Three Basic Principles of Genetics

38 The Principle of Dominance  One gene for a trait may hide the other gene and keep it from being seen (expressed) in the organism Miller, K. R., & Levine, J. S. (2005). Chapter 11: Introduction to Genetics. Prentice Hall biology (North Carolina ed., pp ). Upper Saddle River, N.J.: Prentice Hall.

39 Section 1 Check When Mendel crossed a tall pea plant with a short pea plant, all the offspring plants were tall. In such crosses when only one trait was observed, Mendel called the observed trait dominant. TT T T tt t t All tall plants F1F1 Tall plant Miller, K. R., & Levine, J. S. (2005). Chapter 11: Introduction to Genetics. Prentice Hall biology (North Carolina ed., pp ). Upper Saddle River, N.J.: Prentice Hall.

40 The Principle of Segregation  The two genes for a trait separate, or segregate, during the formation of gametes (meiosis).  This happens when pairs of chromosomes separate during meiosis Miller, K. R., & Levine, J. S. (2005). Chapter 11: Introduction to Genetics. Prentice Hall biology (North Carolina ed., pp ). Upper Saddle River, N.J.: Prentice Hall.

41 The Principle of Independent Assortment  Genes for different traits separate independently during the formation of gametes. Miller, K. R., & Levine, J. S. (2005). Chapter 11: Introduction to Genetics. Prentice Hall biology (North Carolina ed., pp ). Upper Saddle River, N.J.: Prentice Hall.

42 Sex Chromosomes  X and Y chromosomes  Determine the sex of the offspring  Females have two large XX chromosomes  Males have an X and a smaller Y chromosome (XY). Miller, K. R., & Levine, J. S. (2005). Chapter 11: Introduction to Genetics. Prentice Hall biology (North Carolina ed., pp ). Upper Saddle River, N.J.: Prentice Hall. Miller, K. R., & Levine, J. S. (2005). Chapter 14: The Human Genome.Prentice Hall biology (North Carolina ed., pp ). Upper Saddle River, N.J.: Prentice Hall.

43 Sex Chromosomes  All other chromosomes are autosomes.  Human sperm contain 22 autosomes and an X or Y chromosome  Human eggs contain 22 autosomes and an X chromosome Miller, K. R., & Levine, J. S. (2005). Chapter 11: Introduction to Genetics. Prentice Hall biology (North Carolina ed., pp ). Upper Saddle River, N.J.: Prentice Hall. Miller, K. R., & Levine, J. S. (2005). Chapter 14: The Human Genome.Prentice Hall biology (North Carolina ed., pp ). Upper Saddle River, N.J.: Prentice Hall.

44 Sex-linked Traits  Most are carried on the X chromosome  Also called X-linked traits  Hemophilia and color blindness are recessive sex-linked traits carried on the X-chromosome  Males show recessive traits more than females Miller, K. R., & Levine, J. S. (2005). Chapter 11: Introduction to Genetics. Prentice Hall biology (North Carolina ed., pp ). Upper Saddle River, N.J.: Prentice Hall. Miller, K. R., & Levine, J. S. (2005). Chapter 14: The Human Genome.Prentice Hall biology (North Carolina ed., pp ). Upper Saddle River, N.J.: Prentice Hall.

45 Sex-linked Traits  Males get only one allele for a sex- linked trait carried on the X chromosome (nothing on Y)  Females have a second X chromosome that carries another allele that can hide recessive traits Miller, K. R., & Levine, J. S. (2005). Chapter 11: Introduction to Genetics. Prentice Hall biology (North Carolina ed., pp ). Upper Saddle River, N.J.: Prentice Hall. Miller, K. R., & Levine, J. S. (2005). Chapter 14: The Human Genome.Prentice Hall biology (North Carolina ed., pp ). Upper Saddle River, N.J.: Prentice Hall.

46 Sex-linked Traits  Females who have recessive alleles but show the dominant trait are called carriers  A woman can have normal vision but carry the recessive allele for colorblindness Miller, K. R., & Levine, J. S. (2005). Chapter 11: Introduction to Genetics. Prentice Hall biology (North Carolina ed., pp ). Upper Saddle River, N.J.: Prentice Hall. Miller, K. R., & Levine, J. S. (2005). Chapter 14: The Human Genome.Prentice Hall biology (North Carolina ed., pp ). Upper Saddle River, N.J.: Prentice Hall.

47 Test Cross  Done to determine the genotypes of organisms that show dominant traits  Unknown genotype organism is crossed with a homozygous recessive (Example: tt) Miller, K. R., & Levine, J. S. (2005). Chapter 11: Introduction to Genetics. Prentice Hall biology (North Carolina ed., pp ). Upper Saddle River, N.J.: Prentice Hall. Miller, K. R., & Levine, J. S. (2005). Chapter 14: The Human Genome.Prentice Hall biology (North Carolina ed., pp ). Upper Saddle River, N.J.: Prentice Hall.

48 Test Cross  If all offspring have the dominant trait then the genotype is probably pure (TT x tt)  If some of the offspring show the recessive trait, then the genotype is heterozygous.(Tt x tt) Miller, K. R., & Levine, J. S. (2005). Chapter 11: Introduction to Genetics. Prentice Hall biology (North Carolina ed., pp ). Upper Saddle River, N.J.: Prentice Hall. Miller, K. R., & Levine, J. S. (2005). Chapter 14: The Human Genome.Prentice Hall biology (North Carolina ed., pp ). Upper Saddle River, N.J.: Prentice Hall.

49 Pedigree Study  Method of determining the genotype of individuals by looking at inheritance patterns Miller, K. R., & Levine, J. S. (2005). Chapter 14: The Human Genome.Prentice Hall biology (North Carolina ed., pp ). Upper Saddle River, N.J.: Prentice Hall.

50 Human Genetics  23 pairs of chromosomes (46 total)  Pedigrees are used to trace genetic traits Miller, K. R., & Levine, J. S. (2005). Chapter 11: Introduction to Genetics. Prentice Hall biology (North Carolina ed., pp ). Upper Saddle River, N.J.: Prentice Hall.

51 Pedigrees illustrate inheritance Male Female Affected male Affected female Mating Parents Siblings Known heterozygotes for recessive allele Death Miller, K. R., & Levine, J. S. (2005). Chapter 14: The Human Genome.Prentice Hall biology (North Carolina ed., pp ). Upper Saddle River, N.J.: Prentice Hall.

52 In a pedigree, a circle represents a female; a square represents a male. Pedigrees illustrate inheritance Female Male ? I II III IV Miller, K. R., & Levine, J. S. (2005). Chapter 14: The Human Genome.Prentice Hall biology (North Carolina ed., pp ). Upper Saddle River, N.J.: Prentice Hall.

53 Highlighted circles and squares represent individuals showing the trait being studied. ? I II III IV Pedigrees illustrate inheritance Miller, K. R., & Levine, J. S. (2005). Chapter 14: The Human Genome.Prentice Hall biology (North Carolina ed., pp ). Upper Saddle River, N.J.: Prentice Hall.

54 Pedigrees illustrate inheritance Circles and squares that are not highlighted represent individuals that do not show trait. ? I II III IV Miller, K. R., & Levine, J. S. (2005). Chapter 14: The Human Genome.Prentice Hall biology (North Carolina ed., pp ). Upper Saddle River, N.J.: Prentice Hall.

55 A half-shaded circle or square represents a carrier, a heterozygous individual. Pedigrees illustrate inheritance Miller, K. R., & Levine, J. S. (2005). Chapter 14: The Human Genome.Prentice Hall biology (North Carolina ed., pp ). Upper Saddle River, N.J.: Prentice Hall.

56 ? I II III IV Pedigrees illustrate inheritance A horizontal line connecting a circle and a square indicates that the individuals are parents, and a vertical line connects parents with their offspring. Miller, K. R., & Levine, J. S. (2005). Chapter 14: The Human Genome.Prentice Hall biology (North Carolina ed., pp ). Upper Saddle River, N.J.: Prentice Hall.

57 Pedigrees illustrate inheritance Each horizontal row of circles and squares in a pedigree designates a generation, with the most recent generation shown at the bottom ? I II III IV Miller, K. R., & Levine, J. S. (2005). Chapter 14: The Human Genome.Prentice Hall biology (North Carolina ed., pp ). Upper Saddle River, N.J.: Prentice Hall.

58 ? Pedigrees illustrate inheritance The generations are identified in sequence by Roman numerals, and each individual is given an Arabic number. I II III IV Miller, K. R., & Levine, J. S. (2005). Chapter 14: The Human Genome.Prentice Hall biology (North Carolina ed., pp ). Upper Saddle River, N.J.: Prentice Hall.

59 Pedigree Chart

60 Simple Pedigree

61 Nondisjunction  Chromosome pairs do not separate correctly  One gamete has too many the other too few Miller, K. R., & Levine, J. S. (2005). Chapter 14: The Human Genome.Prentice Hall biology (North Carolina ed., pp ). Upper Saddle River, N.J.: Prentice Hall.

62 Nondisjunction Examples:  Trisomy 21 - Down Syndrome (extra chromosome 21) Miller, K. R., & Levine, J. S. (2005). Chapter 14: The Human Genome.Prentice Hall biology (North Carolina ed., pp ). Upper Saddle River, N.J.: Prentice Hall.

63 Down Syndrome

64  XXY syndrome (Klinefelter Syndrome) Miller, K. R., & Levine, J. S. (2005). Chapter 14: The Human Genome.Prentice Hall biology (North Carolina ed., pp ). Upper Saddle River, N.J.: Prentice Hall.

65 Genetic Disorders  Most caused by recessive alleles  Cystic fibrosis  Sickle-cell anemia  Phenylketonuria (PKU)  Tay-Sachs disease Miller, K. R., & Levine, J. S. (2005). Chapter 14: The Human Genome.Prentice Hall biology (North Carolina ed., pp ). Upper Saddle River, N.J.: Prentice Hall.

66 Karyotype  Chart of chromosome pairs  Shows unusual number of chromosomes  Can detect trisomy 21 (Down syndrome)  Identifies male or female Miller, K. R., & Levine, J. S. (2005). Chapter 14: The Human Genome.Prentice Hall biology (North Carolina ed., pp ). Upper Saddle River, N.J.: Prentice Hall.

67 Karyotype Normal Female

68

69 Karyotype Female with Down Syndrome

70 Autosomal Disorders in Humans 14-1

71 Dihybrid Cross RYRyrYry RYRRYYRRYyRrYYRrYy RyRRYyRRyyRrYyRryy rYRrYYRrYyrrYYrrYy ryRrYyRryyrrYyrryy RrYy x RrYy 11-3

72 Extra Studying While all of these chapters where not used in this Power Point, you may find it useful to go and read, or re-read, the following chapters in your text book. Chapter 11: Introduction to Genetics Chapter 12: DNA and RNA Chapter 13: Genetic Engineering Chapter 14: The Human Genome Chapter 16: Evolution of Populations Underlined Chapters are covered in Power Point.

73 Bibliography Miller, K. R., & Levine, J. S. (2005). Chapter 11: Introduction to Genetics. Prentice Hall biology (North Carolina ed., pp ). Upper Saddle River, N.J.: Prentice Hall. Miller, K. R., & Levine, J. S. (2005). Chapter 12: DNA and RNA. Prentice Hall biology (North Carolina ed., pp ). Upper Saddle River, N.J.: Prentice Hall. Miller, K. R., & Levine, J. S. (2005). Chapter 13: Genetic Engineering. Prentice Hall biology (North Carolina ed., pp ). Upper Saddle River, N.J.: Prentice Hall. Miller, K. R., & Levine, J. S. (2005). Chapter 14: The Human Genome.Prentice Hall biology (North Carolina ed., pp ). Upper Saddle River, N.J.: Prentice Hall. Miller, K. R., & Levine, J. S. (2005). Chapter 16: Evolution of Populations. Prentice Hall biology (North Carolina ed., pp ). Upper Saddle River, N.J.: Prentice Hall.


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