Genetic Continuity

1. Genetic Continuity Pg. 78-195

2. Genetic Disorders

3. Achromatopsia Down Syndrome Neural Tube Defects Aicardi Syndrome Epidermolysis Bullosa Noonan Syndrome Albinism Familial Dysautonomia Optic Atrophy Alexander Disease Fibrodysplasia Osteogenesis Imperfecta Alpers’ Disease Fragile X Syndrome Peutz-Jeghers Syndrome Alzheimer’s Disease Deficiency Anemia Phenylketonuria (PKU) Angelman Syndrome Galactosemia Pseudoxanthoma Elasticum Autism Gaucher Disease Progeria

4. Genetic Research The scientist who grew a human ear on the back of a mouse has suggested it may one day be possible to "grow" a liver.

5. Human Skin Equivalent

6. Beck Weathers The biggest loss of life on Everest occurred in May 1996 when eight climbers died in a fierce storm. One American climber, Beck Weathers, was left for dead on the mountain during the storm but he regained consciousness and staggered, snowblind, to safety. He lost both of his hands and his nose to frostbite but survived. Nose regeneration.

7. Regenerated Finger http://www.youtube.com/watch?v=GwcT1ViM-hw&feature=related

10. Reproduction Review Types of Reproduction Asexual reproduction Does not involve sexual intercourse Offspring identical to parent – why? Sexual reproduction Produces offspring by uniting two sex cells (fertilization), one from each parent Produces offspring with a variety of traits – why?

11. Questions? Under what circumstances do cells divide? How does the rate of cell division change? Why do some cells divide quickly while others do not? Why do some cells specialize and others do not? Why do some cells divide while others do not? What makes each cell do such unique functions?

13. Cell Theory Review All living things are made up of one or more cells Approx. 100 trillion cells in your body All cells are made from pre-existing cells by cell division A single cell can create 2 cells through mitosis, cytokinesis Parent cell divides to create 2 daughter cells The cell is the basic unit of life A one celled organism is a living thing One cell can do all of life functions

14. Cells and Genetic Information Genetic info is in DNA DNA is packaged as chromosomes Chromosomes are in the nucleus A human body cell has 46 chromosomes (23 pairs)

15. The Cell Cycle The sequence of events from one cell division to another Is a continuous process that doesn’t pause after each phase Phases help scientists explain mitosis and cytokinesis Mitosis is a short but very important part of the cell cycle

16. Mitosis Cell replicates each DNA molecule (chromosomes doubled) Each chromosome is separated from its copy Daughter cells genetically identical to each other and the parent cell Replication of genetic info ensures future cell divisions Each daughter cell is potential parent cell for next generation # of chromosomes before division = # after All body cells have same genetic info Can still have different shapes and functions

18. The Cell Cycle Interphase Time between nuclear divisions Cells grow, make structural proteins, move nutrients, eliminate wastes, prepare for mitosis – cell lives! Genetic material is called chromatin at this point All the DNA molecules and associated proteins in the nucleus in long, thin strands scattered in the nucleus in a tangled, fibrous mass Each chromosome duplicates itself Original and duplicate attached by a centromere = sister chromatids The pair is considered one chromosome

19. Mitosis Prophase First phase Chromosomes in nucleus become visible under microscope as they shorten and thicken In animal cells: Centriole separates and moves to poles to form spindle In plant cells: No centrioles, but spindle fibres still form nuclear membrane dissolves to allow the separation of chromosomes and cell organelles

20. Mitosis Metaphase Second phase Chromosomes (sister chromatids) move toward equatorial plate Chromosomes are dark, wiry structures attached to spindle fibres most visible at this stage, hard to count because they’re entangled

21. Mitosis Anaphase Third phase Centromeres divide, sister chromatids go to opposite poles of the cell the same # and type of chromosomes should be found at each pole Segments of the chromatids may break apart and may reattach

22. Mitosis Telophase Last phase Chromosomes reach opposite poles of the cell and begin to lengthen Spindle fibres dissolve Nuclear membrane forms

23. The Cell Cycle Cytokinesis Cytoplasm starts to divide In animal cells: A fold develops, pinching the cell into 2 parts In plant cells: A cell plate forms between the 2 chromatin masses and separates them - eventually develops into a new cell wall

24. Cloning The process of forming identical offspring from one cell or tissue Sketch the process on pg. 96/97

25. Cancer Broad group of diseases associated with the uncontrolled and unregulated growth of cells Dangerous because a cell can break off and move to another tissue (mestasis)

26. Meiosis Forms gametes (sex cells) Two stages of cell division # of chromosomes in daughter cell is half the # in parent cell Haploid refers to the # of chromosomes in a gamete (n) Diploid refers to 2 times the # of chromosomes in a gamete (2n) Human offspring have 23 chromosomes from each parent that are paired Paired chromosomes called homologous chromosomes Similar in size, shape, gene arrangement, and gene information Deal with the same traits Each body cell, except sex cells, has 23 homologous chromosome pairs Interact during meiosis During fertilization, haploid sperm cell + haploid egg = diploid zygote Restores the diploid chromosome number in the zygote Zygote begins to divide by mitosis and a multicellular human baby is made

29. Meiosis I Prophase I: Nuclear membrane starts to dissolve, the centriole splits and its parts move to opposite poles within the cell and spindle fibres are made Synapsis Chromosomes come together in homologous pairs Each pair made of 4 chromatids and called a tetrad Crossing over can occur Metaphase I: Homologous chromosomes attach to spindle fibres and line up along equator

30. Meiosis I Anaphase I: Homologous chromosomes segregate Reduction division One member of each homologous pair will be found in each of the new cells consisting of 2 sister chromatids Telophase I: A membrane begins to form around each nucleus Each daughter nuclei has 1 member of the chromosome pair These “daughters” are NOT identical! Cells are now ready for Meiosis II

31. Meiosis II Happens at approx. the same time in each haploid daughter cell Pairs of chromatids will separate and move to opposite poles No replication of chromosomes prior to meiosis II Prophase II: Signals beginning of second division Nuclear membrane dissolves and spindle fibres form Metaphase II: Equatorial lineup Anaphase II: Chromatids separate and move to opposite poles Nuclear membrane forms around chromatids, now called chromosomes Telophase II: Second nuclear division is completed and the second division of cytoplasm occurs 4 haploid daughter cells are produced from each meiotic division

32. Create a comparison organizer for Mitosis vs. Meiosis Venn diagram Sims diffs chart ???

34. Gregor Mendel Scientists originally thought crossbreeding would create a blend of traits Mendel proved that isn’t true When he crossbred round seeds with wrinkled seeds the offspring always had round seeds The round trait dominated whether it was from the male or female parent 1 trait always dominated over the other Tall plants dominated over short, yellow seeds dominated over green Factors control plant traits (genes) and different forms of a gene (alleles) Ex. Green and yellow are different alleles for seed colour Traits expressed most often are dominant, the less frequent are recessive Mendel crossbred 2 hybrid plants with round seeds, but some of the offspring expressed the gene for wrinkled seeds (Figure 5, Pg. 132)

35. Creating a personal Profile Try this pg. 133

36. Single-Trait Inheritance Terms: Genotype: refers to the alleles that an organism contains for a particular trait, ex. TT/Tt for a tall plant, tt for a short plant Phenotype: the observable traits of an individual, ex. Tall or short Homozygous: describes genotypes with 2 of the same alleles, ex. TT or tt Heterozygous: describes genotypes with two different alleles, ex. Tt Monohybrid Cross: cross involving 1 allele pair, ex. tt x TT Punnett Square: chart used to show possible combinations of alleles in offspring

37. Steps for Solving Punnett Squares 1. Figure out the genotypes (ex. Heterozygous = Yy, homozygous dominant = BB, homozygous recessive = yy) 2. Break the genotypes down into gametes (ex. Yy = Y and y) 3. Use the gametes in a Punnett square by writing them across the top and left side

38. A plant that is heterozygous tall is crossed with a short plant. Determine the genotypes and phenotypes of the F1 generation.

39. Do Monohybrid Cross Practice Problems

40. Multiple Alleles Possible to have more than 2 different alleles for 1 gene Ex. Fruit flies have many possible eye colours (wild type is dominant over apricot, which dominates over honey, which dominates over white) Ex. Blood types Capital letters and superscripts are used to express the different alleles and their combinations See Table 1, Pg. 143

41. Incomplete Dominance and Codominance Capital letters and superscripts are used to express the different alleles and their combinations Incomplete dominance When two alleles are equally dominant, they interact to create a new phenotype Ex. Red snapdragons + white snapdragons = pink snapdragons CRCR + CWCW = CRCW Codominance Both alleles are expressed at the same time Ex. Red bull + white cow = roan calf (red and white hair) HRHR + HWHW = HRHW

42. Try This! An extra finger is a rare human trait, but is due to a dominant gene. When one parent is normal and the other parent has an extra finger, but is heterozygous for the condition, what is the probability that their children will be normal?

43. Answer to Try This

44. Test Cross Often performed to determine the genotype of a dominant phenotype Always performed between the unknown genotype and a homozygous recessive type If any offspring show the recessive trait, the dominant individual must be heterozygous If all offspring show the dominant trait, the dominant individual must be homozygous Must have numerous repeats of the cross to ensure valid results

45. Sex-linked Traits Traits located on the sex chromosomes We will focus on recessive traits that are carried on the x-chromosome but “missing” on the y-chromosome Observed more often in males (no other allele to mask one recessive allele) Use X and Y with superscripts to solve these problems (see pg. 166 for example)

46. Dihybrid Crosses Express parental genotypes and use foil rule to determine gamete genotypes (4 per parent) Punnett square will have to be a 4x4 grid instead of a 2x2 grid Offspring will have 4 letters, 2 of each type List the alleles for one gene first (dominant alleles first) and then the alleles for the other gene

47. Pedigree Charts Presentation of a family tree that allows patterns of inheritance to be followed for a gene Use symbols that identify gender, relationships between individuals, and if an individual expresses a trait or carries the allele as part of a heterozygous genotype

48. Genetic Screening Before insulin could be taken from animals many people who had the recessive homozygous alleles for the condition died before passing their genes on to offspring Genetic screening works to detect these conditions before conception Prenatal testing can be used to determine the sex of the offspring and to identify the presence of genetic conditions Amniocentesis and CVS are commonly used

49. Virtual Fly Simulation

50. The Source of Heredity A gene can effect how nerve cells receive information All genes interact with the environment How much is a phenotype affected by genes and how much is it affected by the environment? Ex. The same species of fish develop differently depending on water temp. Ex. Himalayan rabbits are partially black if raised at low temperatures, and white if raised at high temperatures

51. Early Developments in Genetics We know genes are responsible for heredity 1831- nucleus discovered Many misconceptions were cleared up by 1865, after Mendel’s work Known that egg and sperm unite to produce a zygote Better microscopes being developed around the time of Mendel’s work This created cytology, the study of cell formation, structure, and function 1882- Walter Fleming described the separation of threads in the nucleus during cell division 1882- Edouard van Benden noticed that roundworm sperm and egg cells have 2 chromosomes, but fertilized eggs have 4 1887- August Weisman theorized that a special division takes place in sex cells 1900- Mendel’s experiments rediscovered and their significance realized

52. Development of the Chromosomal Theory 1902- Walter S. Sutton & Theodor Boveri separately observed that chromosomes are in pairs that separated during meiosis Chromosomes formed new pairs when the egg and sperm united Supported Mendel’s theory of inheritance based on paired factors These paired factors are now called alleles -- 1 allele from each sex cell Cellular evidence proved the formation of new allele combinations in further generations Chromosome behaviour during gamete formation helped explain Mendel’s laws of segregation and independent assortment Sutton and Boveri knew phenotypes weren’t dependent on 1 parent Cells in the egg and sperm determine heredity Determined that Mendel’s factors were carried on chromosomes Sutton hypothesized that chromosomes carry genes and genes on the same chromosome are considered linked

53. Chromosomal Theory Improvement of the microscope led to advances in cytology and the union of cell biology and genetics Summary of the Chromosomal Theory of Genetics: Chromosomes carry genes, the units of heredity Paired chromosomes segregate during meiosis. Each sex cell has half the # of chromosomes found in the somatic cells (not sex cells). This is why a gamete has only 1 of each paired allele Chromosomes arrange independently during meiosis Each gamete gets 1 member of each chromosome pair The pairs don’t influence the movement of each other

54. Morgan’s Experiments and Sex Linkage Used fruit flies to study the principles of inheritance Reproduce quickly and offspring can mate shortly after leaving the egg (possible to study many generations at one time) Observed mutations linked to other traits (Table 1, Pg. 164) Saw a white-eyed male in with the red-eyed offspring and determined that white eyes are a mutation Mated a white-eyed male with a red-eyed female, all the offspring had red eyes Continued to breed different generations and discovered that only males had white eyes Realized Y chromosome doesn’t carry the gene for eye colour Sex-linked trait because gene is located on sex chromosomes Male offspring always inherit sex-linked traits from the mother Sex-linked genes are also found in humans Ex. Red-green colourblindness

55. Barr Bodies Dr. Murray Barr discovered a small,dark spot of chromatin in the nucleus of a female mammal cell, now called a Barr body Caused by 1 of the X chromosomes becoming inactive in each cell Showed that not all female cells are identical Some cells express a certain trait while others show a different form Has been estimated that the X chromosome carries 100 to 200 different genes This means there are many sex-linked traits, like hemophilia, nearsightedness etc. that affect males more than females The Y chromosome carries the information determining gender

56. Looking Inside the Chromosome Nucleus of every bodily cell contains DNA DNA is the only molecule known to be capable of replicating and allowing cellular reproduction DNA is the way hereditary information passes from generation to generation and contains instructions to ensure life continues As organisms grow, cells specialize according to the instructions given by DNA In older organisms, DNA instructs how to repair and replace worn cell parts This info is carried by chemical messages between the nucleus and cytoplasm DNA has all the instructions to make you unique Proteins, made up of nucleic acids, are the major structural and functional components of all cells Nucleotides are the basic units of nucleic acids

57. Video: DNA Structure

58. Discovering the Structure of DNA Rosalind Franklin developed a technique that photographed the DNA molecule and produced photos showing its helical structure and where the phosphate sugars are located Scientists knew DNA was made up of sugars, phosphate, and 4 different nitrogenous bases (A, T, G, C), but they didn’t know the arrangement New research showed there are equal amounts of G and C, and equal amounts of A and T Suggested that the bases were arranged in pairs James Watson understood the chemical data, while Francis Crick could understand the X-ray diffraction results Together they developed a 3D model of DNA they presented in 1953

59. The Structure of DNA Double helix, like a spiral ladder Sugars and phosphates make the backbone of the staircase, and the nitrogenous bases make the rungs Purines pair with pyramidines

60. Genetic Research and Technologies

61. Genetic Research and Technologies Cystic Fibrosis: Inherited disorder associated with 1 gene that produces a protein called CFTR One allele must be inherited from each parent A team at the Hospital for Sick Children identified the gene in 1989 Possible to correct the basic defect by delivering a normal version of the CFTR protein in mice Muscular Dystrophy: Group of genetic disorders causing muscle deterioration Some forms are linked to non-sex cells and can occur in males and females Other forms are sex-linked and affect males, but females may show mild symptoms (Table 2, Pg. 182)

62. DNA Fingerprinting Long stretches of the DNA molecule are similar from person to person Less than 1% of DNA is unique to an individual DNA samples can be taken from skin samples, hair, semen, or blood They are cut with restriction enzymes at specific sites and reproducible DNA fragments are created Location and # of cuts are distinct for each person, so DNA profiles are unique to each person Fragments are transferred to a nylon sheet and a radioactive marker identifies the unique sequence of the DNA chain The sheet is placed against an X-ray film and black bands appear where markers have attached to the segments A print is made from the film and used to compare samples

63. Gene Therapy Replaces defective genes with normal genes to cure genetic conditions Three possible strategies: Insert a normal gene into position on the chromosome of the affected cell Chemically modify the defective gene to hopefully recode the genetic message Use surgery to replace the defective gene with a normal gene 1990- 1st clinical use on 4 year old girl who had insufficient amounts of ADA, an enzyme A genetically modified virus was used to carry a normal ADA gene into her immune cells so the right enzyme would be produced The trick to using a virus to insert new genetic information is to ensure it will be placed in the right location Many projects are currently underway to hopefully help those suffering from a variety of genetic disorders

64. What is the phenotypic ratio of the offspring of the following Drosophilia?