Final project
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Mutations are changes in DNA that may occur in somatic or germ cells. Most mutations are neutral, but some can be harmful, causing diseases like cancer, or beneficial by improving survival. Mutations can involve chromosomes, such as deletions, inversions, duplications, or translocations, or genes through point mutations, insertions, deletions, or frameshifts. Examples of diseases caused by mutations include Down syndrome from chromosome nondisjunction, sickle cell anemia from a single nucleotide substitution, and cystic fibrosis from a three base pair deletion.
Final project
- 4. What Are Mutations?What Are Mutations? • Changes in the nucleotide sequence of DNA • May occur in somatic cells (aren’t passed to offspring) • May occur in gametes (eggs & sperm) and be passed to offspring
- 5. Are Mutations Helpful or Harmful? • Mutations happen regularly • Almost all mutations are neutral • Chemicals & UV radiation cause mutations • Many mutations are repaired by enzymes
- 6. Are Mutations Helpful or Harmful? • Some type of skin cancers and leukemia result from somatic mutations • Some mutations may improve an organism’s survival (beneficial)
- 8. Chromosome Mutations • May Involve: – Changing the structure of a chromosome – The loss or gain of part of a chromosome
- 9. Chromosome Mutations • Five types exist: – Deletion – Inversion – Translocation – Nondisjunction – Duplication
- 10. Deletion • Due to breakage • A piece of a chromosome is lost
- 11. Inversion • Chromosome segment breaks off • Segment flips around backwards • Segment reattaches
- 12. Duplication • Occurs when a gene sequence is repeated
- 13. Translocation • Involves two chromosomes that aren’t homologous • Part of one chromosome is transferred to another chromosomes
- 14. Translocation
- 15. Nondisjunction • Failure of chromosomes to separate during meiosis • Causes gamete to have too many or too few chromosomes • Disorders: – Down Syndrome – three 21st chromosomes – Turner Syndrome – single X chromosome – Klinefelter’s Syndrome – XXY chromosomes
- 19. Gene Mutations • Change in the nucleotide sequence of a gene • May only involve a single nucleotide • May be due to copying errors, chemicals, viruses, etc.
- 20. Types of Gene Mutations • Include: – Point Mutations – Substitutions – Insertions – Deletions – Frameshift
- 21. Point Mutation • Change of a single nucleotide • Includes the deletion, insertion, or substitution of ONE nucleotide in a gene
- 22. Point Mutation • Sickle Cell disease is the result of one nucleotide substitution • Occurs in the hemoglobin gene
- 23. Frameshift Mutation • Inserting or deleting one or more nucleotides • Changes the “reading frame” like changing a sentence • Proteins built incorrectly
- 24. Frameshift Mutation • Original: – The fat cat ate the wee rat. • Frame Shift (“a” added): – The fat caa tet hew eer at.
- 28. Down’s Syndrome •Caused by non-disjunction of the 21st chromosome. •This means that the individual has a trisomy (3 – 2lst chromosomes).
- 29. Down’s Syndrome or Trisomy 21
- 30. Symptoms of Down Syndrome •Upward slant to eyes. •Small ears that fold over at the top. •Small, flattened nose. •Small mouth, making tongue appear large. •Short neck. •Small hands with short fingers.
- 31. Kleinfelter’s syndrome (or Klinefleter’s) •Disorder occurring due to nondisjunction of the X chromosome. •The Sperm containing both X and Y combines with an egg containing the X, results in a male child. •The egg may contribute the extra X chromosome.
- 32. XXY •Males with some development of breast tissue normally seen in females. •Little body hair is present, and such person are typically tall, have small testes. • Infertility results from absent sperm. •Evidence of mental retardation may or may not be present.
- 33. Turner’s Syndrome •Turner syndrome is associated with underdeveloped ovaries, short stature, webbed, and is only in women. •Bull neck, and broad chest. Individuals are sterile, and lack expected secondary sexual characteristics. • Mental retardation typically not evident. •Chromosomal or monogenic
- 34. Sickle Cell Anemia •An inherited, chronic disease in which the red blood cells, normally disc-shaped, become crescent shaped. As a result, they function abnormally and cause small blood clots. These clots give rise to recurrent painful episodes called "sickle cell pain crises".
- 35. Sickle Cell •Sickle cell disease is most commonly found in African American populations. This disease was discovered over 80 years ago, but has not been given the attention it deserves.
- 36. Cystic Fibrosis (CF) •Monogenic •Cause: deletion of only 3 bases on chromosome 7 •Fluid in lungs, potential respiratory failure •Common among Caucasians…1 in 20 are carriers
- 37. Tay-Sachs disease •Monogenic, autosomal recessive •Central nervous system degrades, ultimately causing death. •Most common among people of Jewish, eastern Europe descent.
- 38. Muscular Dystrophy •What Is Muscular Dystrophy? Muscular dystrophy is a disease in which the muscles of the body get weaker and weaker and slowly stop working because of a lack of a certain protein (see the relationship to genetics?) •Can be passed on by one or both parents, depending on the form of MD (therefore is autosomal dominant and recessive)
- 39. Hemophilia, the royal disease •Hemophilia is the oldest known hereditary bleeding disorder. •Caused by a recessive gene on the X chromosome. •There are about 20,000 hemophilia patients in the United States. •One can bleed to death with small cuts.
- 40. Hemophilia, the royal disease •The severity of hemophilia is related to the amount of the clotting factor in the blood. About 70% of hemophilia patients have less than one percent of the normal amount and, thus, have severe hemophilia.
- 41. Huntington’s Disease •Huntington's disease (HD) is an inherited, degenerative brain disorder which results in an eventual loss of both mental and physical control. The disease is also known as Huntington's chorea. Chorea means "dance-like movements" and refers to the uncontrolled motions often associated with the disease.
- 42. Huntington’s •Looking back at the pedigree chart is Huntington’s dominant or recessive? •Scientists have discovered that the abnormal protein produced by the Huntington's disease gene, which contains an elongated stretch of amino acids called glutamines, binds more tightly to HAP-1 than the normal protein does.
- 43. Albinism •Patients are unable to produce skin or eye pigments, and thus are light-sensitive •Autosomal recessive
- 44. Conclusion • Earlier mutations were considered as a natural and a harmful phenemenon. But science has proved this as a misconception. According to scientists mutation is one of the powerful tool that man has developed over a period of time. So its area of utilisation totally depends on human mind. It is such a thing which can produce as well as destroy. So finally it all depends on who uses it and for what purpose.
- 45. Source • Wikipedia. • 9th std science textbook. • 10th std textbook.