1. From Peas and fruit flies to humans

2. What is a genome??? All the genetic information (genes) thatmake up an organism 3. What makes ushuman? Analyze humanchromosome Karotype Picture of all the chromosomesin an organism Autosomes CHROMOSOMES 1-44 (pairs 1-22) Autosomal chromsomes Sex chromosomes Determine a persons sex (maleXY or female XX) Chromosome 45 and 46 (set 23) 4. Pedigree Charts Shows relationships within a family Genetic counselors use these to infer thegenotypes of family members Look at each generation different symbolsused 5. Disorders can be recessive ordominant 6. Recessive disorders Disorder phenylketonuria (PKU) Caused by an autosomal recessive alleleon chromosome 12 People with this disorder lack the enzymeto break down phenylalanine (amino acidfound in milk and many other foods) In newborns, this causes a build up ofphenylalanine in tissues during the first fewyears of life and lead to mental retardation Newborns are commonly tested for PKU andthen put on a low phenylalanine diet if they havethe disorder 7. Autosomal Recessive Allele Tay-Sachs Disease Recessive allele in Jewish families of central andeastern Europe ancestry Lack the enzyme to break down lipids in neural cells Lipid accumulation in brain cells Leads to nervous system break-down and death in the first few years of life 8. Autosomal RecessiveDisorders Cystic Fibrosis Do not have the gene thatregulates mucus production Excess mucus in lungs,digestive tract, and liver Increased susceptibility todisorders Lung transplants usuallyneeded after childhood 9. Autosomal DominantDisorders You will express disorder ifyou are homozygous orheterozygous dominant forthat trait You also have higher chances of passing onto your children Dwarfism (achondroplasia) Huntingtons Disease Nervous system disorder 10. Co-Dominant AllelesDisorders Sickle cell anemia 1/500 African Americans havethe disorder Co-dominant allele Causes blockages in bloodvessels, preventing oxygen fromgetting to other cells and tissues Beneficial in central and eastAfrica because it helped destroymalaria If you had SCA, your body would destroy the sickle cells to protect itself and in the process, destroy the malaria parasite as well 11. Sex-Linked Disorders Many sex-linked genes arefound on x-chromosome Many genetic disordersare sex-linked Males have just ONE xchromosome, so whateverthe X chromosome iscarrying (dominant orrecessive) will beexpressed Fathers can pass it to theirdaughters and the disordercan show up in thedaughters sons 12. Sex-linked Disorders Red-green Color-blindness 1/10 men 1/100 women Hemophilia Two important genes on x-chr controlblood clotting Person with disorder can die from minorcuts Recessive allele in either gene can causeit Duchenne Muscular Dystrophy Caused by defective version of a gene fora muscle protein Progressive weakening and loss ofskeletal muscle1/3000 males 13. Sex-linked genetic practiceproblem1.In humans the gene from normal blood clotting, H, is dominate to the gene forhemophilia, h. This is a sex-linked trait found on the X chromosome. A woman withnormal blood clotting has four children. They are a normal son, a hemophiliac son,and two normal daughters. The father has normal blood clotting. What is theprobable genotype for each member of the family?2. In humans, the genes for colorblindness and hemophilia are both located on the X chromosome with no corresponding gene on the Y. These are both recessive alleles. If a man and a woman, both with normal vision, marry and have a colorblind son, draw the Punnett square that illustrates this. If the man dies and the woman remarries to a colorblind man, draw a Punnett square showing the type(s) of children could be expected from her second marriage. How many/what percentage of each could be expected?3. A man with normal vision is XY. What kind(s) of gametes (sperm) can he produce?4. Any woman with normal vision could be XX or XX.Since this woman has a colorblind son (genotype XY), she has to be XX (a carrier).What kind(s) of gametes (eggs) can she produce? 14. Sex Influenced Traits1. Baldness in humans is a dominant, sex-influenced trait. This gene is on the autosomes, not the sex chromosomes, but how it is expressed is influenced by the persons sex (due to hormones present, etc.). A man who is BB or Bb will be bald and will be non-bald only if he is bb. A woman will only be bald if she is BB and non-bald if she is Bb or bb (its almost like B is dominant in males and b is dominant in females). Actually, because of the influence of other sex-related factors, most women who are BB never become totally bald like men do, but rather, their hair becomes thin or sparse. If two parents are heterozygous for baldness, what are the chances of their children being bald? Use a Punnett square to illustrate this. Note: because the sex of a person does make a difference in how the gene is expressed, you need to set this up as a dihybrid cross to account for the sex of the children2. A non-bald man marries a non-bald woman. They have a son and a daughter. If the son becomes bald, what are the chances that his sister will, too? Use a Punnett square to show this cross.3. A non-bald man has to be XYbb. What kind(s) of gametes (sperm) can he produce?4. Any non-bald woman can be XXBb or XXbb. The bald son could be XYBB or XYBb, but since the father is XYbb, we know the son cannot be XYBB (remember the first problem?). The son has to be XYBb, therefore this mother has to be XXBb (if she was XXbb he couldnt have a B). What kind(s) of gametes (eggs) can she produce?5. A womans mother is bald, but her father is not. Her older brother is rapidly going bald. She is an acrobat who hangs by her hair. Should she change her profession before she goes bald, too? Use a Punnett square to show this.6. 15. DNA Review The 2 Fates of DNAProtein Synthesis DNA Replication(when cell is doing is (if cell enters cellnormal job-in G1divisionS-phase) phase of cell cycle) 16. DNA Facts All living things have DNA Prokaryotes-DNA in cytoplasm,simple Contain extra DNA calledPLASMIDS Eukaryotes-DNA in nucleus,complex DNA codes for the same 20 aminoacids in ALL living things It is the UNIVERSAL code..allorganisms have the same A,T,Gand C bases and the same 20a.a., just arranged differently 17. 5The DNA backbonePO4 Putting the DNA backbone togetherbase5 CH2 refer to the 3 and 5 endsO41of the DNAC3 the last trailing carbon O2O P OSounds trivial, butObasethis will be5 CH2IMPORTANT!! O4132OH3 18. Anti-parallelstrands Nucleotides in DNAbackbone are bonded fromphosphate to sugar5 3between 3 & 5 carbons DNA molecule hasdirection complementary strand runsin opposite direction3 5 19. Bonding in DNA hydrogen bonds5 3 covalent phosphodiester bonds35.strong or weak bonds?How do the bonds fit the mechanism for copying DNA? 20. Base pairing in DNA Purines adenine (A) guanine (G) Pyrimidines thymine (T) cytosine (C) Pairing A:T 2 bonds C:G 3 bonds 21. Copying DNA Replication of DNA base pairing allowseach strand to serveas a template for anew strand new strand is 1/2parent template &1/2 new DNA semi-conservative copy process 22. Lets meet the teamDNA Replication Large team of enzymes coordinates replication 23. Important Enzymes DNA Helicase Unzips original DNA strand DNA Polymerase Adds nucleotides to theunzipped sides DNA Ligase Attaches/glues DNAfragments together on oneof the new copies 24. How does DNA replicate itself? Template mechanism What is a template??? PowerPoint presentations. Like the negative of a photograph DNA Replication Process of copying the DNA molecule What phase of the CELL CYCLE? S-phase. 2 strands of double helix separate (Unzips) Each strand acts as a negative for making thenew complementary strand Nucleotides line up one by one following basepairing rules Enzymes (DNA Polymerase and DNA Ligase)link nucleotides together to form 2 new DNAstrands called the daughter strands 25. Fate #2: Protein Synthesis You already know about thiscentraldogma of Biology Just need to know your key players 26. The Protein Synthesis Team DNA mRNA tRNA rRNA Codons Anticodons Amino acids Proteins Introns Exons 27. DNAmRNAprotein DNA TRANSCRIBES tomRNA Process is called transcription mRNA TRANSLATES toproteins Process is calledtranslation mRNA actually makesamino acids, which cometogether to make proteins 28. DNAmRNAamino acids/polypeptide chain(Proteins) DNA codes for an RNA strand The every 3 bases on the RNAstrand code for a specific aminoacid CODON: three sequential basesthat code for a specific a.a. (20a.a. total) Amino acid are strung together tomake a protein (primary structure) Change DNA will change RNAwhich will change amino acids,which change protein 29. TranscriptionDNAmRNAProtein Different form of the samemessage DNA makes singlestranded RNA (U replacesT) RNA leaves nucleus Translation Translate from nucleic acidlanguage to amino acidlanguage Uses codons, 3-baseword that codes forspecific a.a. code for an amino acid Several codons make asentence that translatesto a polypeptide (protein) 30. StartStopCodons Codons AUG UAA UGA UAG 31. Three Types of RNA mRNA tRNA rRNA 32. Three Types of RNA #1 mRNA (messanger RNA) RNA transcribed from DNA template Modified in nucleus before if exits RNA splicing: process in which Introns are removed andexons re joined together to make a continuous codingmRNA molecule Introns Internal non-coding regions of DNA and mRNA Space fillers/jibberish They are cut out of mRNA before it is allowed to leave thenucleus Process is called RNA splicing (processing) Exons (MOST important part of DNA) Coding region of DNA and mRNA that will be translated(Expressed) VERY important part of mRNAit is carrying the messagefrom DNA (def cant cut this out) 33. Three Types of RNA#2 tRNA (transfer RNA) The interpreter Translate 3-letter basecodes into amino acids Carries anti-codon onone end (three lettersopposite of what is onmRNA) Carries amino acid onother end Anti-codon recognizescodon and attaches 34. Three Types of RNA#3 rRNA (ribosomal RNA) Found in ribosome Ribosome composed of 2 subunits: Small subunit for mRNA to attach Large Subunit for two tRNAs to attach P site: holds the tRNA carrying the growing polypeptide chain A site: holds the tRNA that is carrying the next a.a. to be added to the chain When stop codon (UAA, UAG, UGA) is reached, translation ends and polypeptide is released 35. Mutations Occur when there is an error in DNAreplication Def: Change in genetic material Mutagens Physical or chemical agents that cause mutations Ex: high energy radiation (x-ray or UV) Ex. Chemicals (that are similar to DNA but cause incorrect base pairing) 36. Mutation Any change in the nucleotide sequence ofDNA Large or small 2 Main types Point Mutation Base Substitutions Frameshift Mutation Insertions or deletions 37. Base Substitution Replacement of one base or nucleotide withanother Usually do not change amino acid Sometimes causes a change in the proteinmade Silent Mutation When a substitution does not cause a change in theprotein expressed by a gene Remember some codons represent the same aminoacid Example: GAA and GAG both code for Glu 38. Point MutationA point mutation is a simple change in one base ofthe gene sequence. This is equivalent to changingone letter in a sentence, such as this example,where we change the c in cat to an h: Original: The fat cat ate the wee rat. Point Mutation: The fat hat ate the wee rat. 39. Insertion or Deletion Nucleotide is removed or added More disastrous mRNA is read as triplet codes Adding/removing bases changes these threeletter codes Codons downstream from insertion/deletion willbe regrouped and probably code for a non-working protein Result: FRAMESHIFT MUTATION Shift the reading frame of the genetic message 40. Frameshift mutation Original:The fat cat ate the wee rat. Frame Shift: The fat caa tet hew eer at. 41. Chromosomal Mutations Involve changes in the number orstructure of the chromosome 42. Chromosomal Disorders Mechanics of meiosis (where we separatechromosomes) is usually pretty good But nobodys perfectmistakes happen. Most common problem Nondisjunction: when homologouschromosomes fail to separate properly Literally means not coming apart If this occurs, ABNORMAL #s of chromosomesmay find their way into gametes and a disorderof chromosome number may result 43. Nondisjunction If one of the gametes with an ABNORMAL# ends up getting fertilized, MAJORproblems!!! Trisomy: three bodies Occurs when an autosomal chromosome fails toseparate during meiosis When do chrm separate?- Anaphase I and Anaphase 2 One gamete ends up with an extra copy of achromosome and then the fertilized zygote endsup with 3 copies of a chrm instead of 2 Example: Downs Syndrome 44. Down Syndrome Extra copy of chromosome 21 1/800 babys are born with thisdisorder Produces mild to severeretardation Increased susceptibility todiseases, slower development,and higher frequency of birthdefects How can one little extra copycause so many problems? Scientists are still trying to figure thatoutnow that they have used genemapping and identified all the geneson chromosome 21, they can beginexperimenting on this problem 45. Chromosomal Mutations May change location ofgenes on chromosome Include: Deletions: loss of part ofchromosome Duplications: produceextra copies of parts ofchromosome Inversions: reversedirection of chromosome Translocation: when onechromosome breaks offand attaches to another 46. Mutations NOT always harmful Some alter a protein in a beneficialway that may help species in aspecific environment If mutation is present in organismsgametes, it may be passed off to off-spring Mutations are the ULTIMATE sourcefor GENETIC DIVERSITY!!! 47. What is biotechnology? Here are some hints 48. Biotechnology Manipulation of living organisms or theirparts to produce useful products Main use is to improve human healthand food production Seedless fruits Make insulin 49. Genetic engineering The transfer of genes or pieces of DNAfrom one organism into anotherorganism New DNA is a combination of pieces from two different organismscalled recombinant DNA Used to introduce new characteristicsinto organisms and populations Gentically Modified Organisms GMOs 50. How to make recombinantDNA Use DNA from complex organism (human) andtransfer to a simple organism (bacteria) Uses a PLASMID Small circular DNA in bacteria It is called a VECTOR when used in genetic engineering 51. Genetic Engineering Positive/benefits Negatives/Cons Make medicine like Unknown long terminsulin and vaccines effects if ingested byplentiful andhumansinexpensive Harm native, natural Improves crop plants specieslike corn and rice Cross pollination Grow faster andbetween GMOs andstronger wild plants resulting in Resist disease and unwanted hybridsinsects(mockingjays!) Genes can be added ***Decreases geneticto add more vitamins variationto plants