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HUMAN GENETICS

HUMAN GENETICS. What can go wrong?. Chromosome Gene Mutations Mutations. Chromosomal Abnormalities. 1 infant in 200 newborns has a chromosomal abnormality 28% of first trimester miscarriages have a chromosomal abnormality

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HUMAN GENETICS

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  1. HUMAN GENETICS What can go wrong? ChromosomeGeneMutationsMutations

  2. Chromosomal Abnormalities • 1 infant in 200 newborns has a chromosomal abnormality • 28% of first trimester miscarriages have a chromosomal abnormality • Abnormalities in larger chromosomes don’t usually survive

  3. A change in the DNA code of an organism is called a ______________________ Mutations can be _______________ OR ______________

  4. BENEFICIAL MUTATIONS Help an organism survive and reproduce Provide variation in population for natural selection to act upon Ex: White fur if you live in a snowy place Image from: http://www.cheryllavender.com/Snow%20Rabbit.jpg

  5. HARMFUL MUTATIONS Can result in death =___________ (even before birth) Cause a genetic disorder Cause cancer

  6. SOMATIC CELL MUTATIONS If the change happens in a BODY CELL (lung, liver, brain, muscle, etc.) = ______________________ Somatic cell mutations can: ______________________ ______________________ _____________ • BUTwon’t be passed on to offspring

  7. GERM CELL MUTATION If the change happens in Gametes (sperm & eggs) = _______________________ • Can be passed on to offspring

  8. ___________Mutations- Changes in an individual gene __________________Mutations Changes in the number of chromosomes What can go wrong?

  9. ADDITION Putting in extra bases during copying A T T C G A G C T A T T C G T A A G C T

  10. SUBSTITUTION Changes one base for another A T T C G A G C T A T T C G A T T G C T

  11. DELETION Piece of whole chromosome is lost ________________________________________ Image from: http://www.biology-online.org/2/8_mutations.htm

  12. DUPLICATION Piece of DNA is copied too many times ________________________________________________ Image from: http://www.biology-online.org/2/8_mutations.htm

  13. INVERSION Segment flips and reads backwards Image from: http://www.biology-online.org/2/8_mutations.htm

  14. TRANSLOCATION Segment breaks off and joins a different non-homologous chromosome Image from: http://www.biology-online.org/2/8_mutations.htm

  15. GENE MUTATIONS Changes in the DNA code of a single gene   ___________ ____________ ______________________

  16. PROTEINS are built from AMINO ACID subunits Image by: Riedell

  17. Each group of 3 nitrogen bases codes for a different amino acid There are 20 different AMINO ACIDS used by cells to make PROTEINS

  18. Proteins are made by joiningamino acids together in long chains Image from:  http://www.ust.hk/roundtable/hi-tech.series/1_b1.jpg

  19. Harmful Gene Mutations Point mutations – change a _________ base in DNA code Frame shift mutationschange _____________ bases in code

  20. FRAME SHIFT MUTATIONSCaused by changes in code that are NOT multiples of DNA message is read in groups of three nitrogen bases

  21. FRAME SHIFT MUTATIONS thefatcatranandran ____________________ DELETION theatcatranandran _____________________ the fat cat ran and ran the atc atr ana ndr an

  22. FRAME SHIFT MUTATIONSat beginning of gene are more damaging than those at end because more of gene is changed thefatcatranandran ____________________ DELETION near front theatcatranandran _____________________ DELETION near end _____________________ the fat cat ran and ran the atc atr ana ndr an thefatcatranandrn

  23. HUMAN GENETICDISORDERS Caused by Gene Mutations

  24. DELETION Piece of whole chromosome is lost ________________________________________ Image from: http://www.biology-online.org/2/8_mutations.htm

  25. Cri-du-chat (Cat cry) (5p-) • 1 in 50,000 births • More common in girls

  26. Mewing cry in infancy • Missing piece of number 5 • Mental retardation • 50% have heart defects

  27. Prader-Willi Syndrome • Deletion in chromosome 15 • Feeding problems: poor weight gain in infancy, won’t eat • Ages 1-6 excessive, rapid weight gain • Under developed sex organs • Mild to moderate retardation • Obsession with food • Complications from problems associated with obesity (heart attack, high blood pressure, diabetes)

  28. Prader-Willi syndrome Victor at age 1 Victor at age 2

  29. SUBSTITUTION Changes one base for another A T T C G A G C T A T T C T A G C T

  30. A gene that is flipped and reads backwards will not work. A gene that is moved to another chromosome will not separate from its partner during meiosis. One cell can get 2 copies of gene, one cell gets none.

  31. SICKLE CELL ANEMIA CAUSE: (autosomal recessive) A changed to T(glu to val) gene on chromosome #11 that codes for part of hemoglobin protein (carries oxygen in blood)

  32. SICKLE CELL ANEMIA SYMPTOMS: Sickle shaped Red Blood Cells in hh persons Circulatoryproblems Loss of blood cells (anemia) Organ damage DEATH

  33. SICKLE CELL ANEMIA More common in African Americans 1 in 500 = hh 1 in 10 = Hh carriers for gene Hh persons have Sickle cell TRAIT make some normal RBC’s’ ; some sickled cells

  34. Having two copies of gene (hh) makes a person sick Having one copy (Hh)- gives person resistance to MALARIA http://www-klinik.uni-mainz.de/Zentrallabor/Lab-Web/Bilder/Malaria_5.jpg

  35. DELETION Piece of DNA code for one gene is lost ________________________________________ Image from: http://www.biology-online.org/2/8_mutations.htm

  36. Duchenne Muscular Dystrophy CAUSE: (X linked recessive) DELETION in gene that codes for a muscle protein

  37. Duchenne Muscular Dystrophy (DMD) SYMPTOMS: 1 in 3500 male births Appears before age 5 Progressive muscle weakening Most in wheelchair by age 13 Eventually lethal

  38. DUPLICATION Piece of DNA is copied too many times ________________________________________________ Image from: http://www.biology-online.org/2/8_mutations.htm

  39. FRAME SHIFT MUTATIONSChanges multiple bases in code thefatcatranandran ____________________ DUPLICATION thefatcatranandandandandran ___________________________ the fat cat ran and ran the fat cat ran and and and ran

  40. HUNTINGTON’S CAUSE: Autosomal dominant 40-100 CAG Repeats at end of gene on chromosome 4

  41. HUNTINGTON’S SYMPTOMS: Seen in both males and females • Degenerative brain disorder • Symptoms appear age 30-40 (Usually after having children) • Lose ability to walk, think, talk, reason • 50/50 chance of passing it to child

  42. Until now people didn’t know they had the gene, until after they had already had children. Now there is a test to tell if you have the gene before symptoms appear. Would you want to know if there is NO cure?

  43. Genetic disorders can be carried on: AUTOSOMES = ________________ SEX CHROMOSOMES = _______________

  44. OTHER GENETIC DISEASES AUTOSOMAL RECESSIVE • Phenylketonuria • Cystic fibrosis • Albinism X-LINKED RECESSIVE • Color blindness • Hemophilia • Muscular dystrophy AUTOSOMAL DOMINANT • Achondroplasia (Dwarfism) • Huntington’s

  45. HEMOPHILIA CAUSE: change in gene on X chromosome that codes for blood clotting protein SYMPTOMS: More common in males Internal and external bleeding Can result in death transfusions/hospitalization required frequently to stop bleeding

  46. ACHONDROPLASIA(Dwarfism) CAUSE: (Autosomal Dominant on chromosome 4)Most are new mutations in egg or sperm cell, but it can be inherited from parent with gene 1 in 20,000 births 200,000 “little people” worldwide One of oldest known – seen in Egyptian art Normal size torso; short arms and legs Problem with way cartilage changes to bone as bones grow

  47. COLOR BLINDNESS CAUSE: X linked recessive Mutation in gene on X chromosome SYMPTOMS:More common in males (8% of males are colorblind) Can’t distinguish certain colors Most common = red/green

  48. Cystic Fibrosis Mutation in gene on chromosome 7 that codes for protein in membrane that transports chloride ions

  49. Cystic Fibrosis Autosomal recessive Symptoms:More common in Caucasians Make extra thick mucous in lungs and pancreas which leads to respiratory and digestive complications Salty skin is clue

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