mutations
DESCRIPTION
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. Are Mutations Helpful or Harmful?. Mutations happen regularly - PowerPoint PPT PresentationTRANSCRIPT
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Mutations
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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
![Page 3: Mutations](https://reader036.vdocument.in/reader036/viewer/2022070404/56813b2f550346895da3fa8f/html5/thumbnails/3.jpg)
Are Mutations Helpful or Harmful?
• Mutations happen regularly
• Almost all mutations are neutral
• Chemicals & UV radiation cause mutations
• Many mutations are repaired by enzymes
![Page 4: Mutations](https://reader036.vdocument.in/reader036/viewer/2022070404/56813b2f550346895da3fa8f/html5/thumbnails/4.jpg)
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)
![Page 5: Mutations](https://reader036.vdocument.in/reader036/viewer/2022070404/56813b2f550346895da3fa8f/html5/thumbnails/5.jpg)
Types of Mutations
![Page 6: Mutations](https://reader036.vdocument.in/reader036/viewer/2022070404/56813b2f550346895da3fa8f/html5/thumbnails/6.jpg)
Chromosome Mutations
• May Involve:–Changing
the structure of a chromosome
–The loss or gain of part of a chromosome
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Chromosome Mutations
• Five types exist:–Deletion–Inversion–Translocation–Nondisjunction
–Duplication
![Page 8: Mutations](https://reader036.vdocument.in/reader036/viewer/2022070404/56813b2f550346895da3fa8f/html5/thumbnails/8.jpg)
Deletion
• Due to breakage• A piece of a
chromosome is lost
![Page 9: Mutations](https://reader036.vdocument.in/reader036/viewer/2022070404/56813b2f550346895da3fa8f/html5/thumbnails/9.jpg)
Inversion
• Chromosome segment breaks off
• Segment flips around backwards
• Segment reattaches
![Page 10: Mutations](https://reader036.vdocument.in/reader036/viewer/2022070404/56813b2f550346895da3fa8f/html5/thumbnails/10.jpg)
Duplication
• Occurs when a gene sequence is repeated
![Page 11: Mutations](https://reader036.vdocument.in/reader036/viewer/2022070404/56813b2f550346895da3fa8f/html5/thumbnails/11.jpg)
Translocation
• Involves two chromosomes that aren’t homologous
• Part of one chromosome is transferred to another chromosomes
![Page 12: Mutations](https://reader036.vdocument.in/reader036/viewer/2022070404/56813b2f550346895da3fa8f/html5/thumbnails/12.jpg)
Translocation
![Page 13: Mutations](https://reader036.vdocument.in/reader036/viewer/2022070404/56813b2f550346895da3fa8f/html5/thumbnails/13.jpg)
Nondisjunction• Failure of chromosomes to
separate during meiosis• Causes gamete to have too
many or too few chromosomes
• Disorders:– Turner Syndrome – single X
chromosome– Klinefelter’s Syndrome – XXY
chromosomes
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Chromosome Mutation Animation
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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.
![Page 18: Mutations](https://reader036.vdocument.in/reader036/viewer/2022070404/56813b2f550346895da3fa8f/html5/thumbnails/18.jpg)
Types of Gene Mutations
• Include:–Point Mutations–Substitutions–Insertions–Deletions–Frameshift
![Page 19: Mutations](https://reader036.vdocument.in/reader036/viewer/2022070404/56813b2f550346895da3fa8f/html5/thumbnails/19.jpg)
Point Mutation
• Change of a single nucleotide
• Includes the deletion, insertion, or substitution of ONE nucleotide in a gene
![Page 20: Mutations](https://reader036.vdocument.in/reader036/viewer/2022070404/56813b2f550346895da3fa8f/html5/thumbnails/20.jpg)
Point Mutation
• Sickle Cell disease is the result of one nucleotide substitution
• Occurs in the hemoglobin gene
![Page 21: Mutations](https://reader036.vdocument.in/reader036/viewer/2022070404/56813b2f550346895da3fa8f/html5/thumbnails/21.jpg)
Frameshift Mutation
• Inserting or deleting one or more nucleotides
• Changes the “reading frame” like changing a sentence
• Proteins built incorrectly
![Page 22: Mutations](https://reader036.vdocument.in/reader036/viewer/2022070404/56813b2f550346895da3fa8f/html5/thumbnails/22.jpg)
Frameshift Mutation
• Original:–The fat cat ate the wee rat.
• Frame Shift (“a” added):– The fat caa tet hew eer at.
![Page 23: Mutations](https://reader036.vdocument.in/reader036/viewer/2022070404/56813b2f550346895da3fa8f/html5/thumbnails/23.jpg)
Amino Acid Sequence Changed
![Page 24: Mutations](https://reader036.vdocument.in/reader036/viewer/2022070404/56813b2f550346895da3fa8f/html5/thumbnails/24.jpg)
Gene Mutation Animation
![Page 25: Mutations](https://reader036.vdocument.in/reader036/viewer/2022070404/56813b2f550346895da3fa8f/html5/thumbnails/25.jpg)
FYI
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Normal Male
262n = 46
![Page 27: Mutations](https://reader036.vdocument.in/reader036/viewer/2022070404/56813b2f550346895da3fa8f/html5/thumbnails/27.jpg)
Normal Female
272n = 46
![Page 28: Mutations](https://reader036.vdocument.in/reader036/viewer/2022070404/56813b2f550346895da3fa8f/html5/thumbnails/28.jpg)
Male, Trisomy 21 (Down’s)
282n = 47
![Page 29: Mutations](https://reader036.vdocument.in/reader036/viewer/2022070404/56813b2f550346895da3fa8f/html5/thumbnails/29.jpg)
Female Down’s Syndrome
292n = 47
![Page 30: Mutations](https://reader036.vdocument.in/reader036/viewer/2022070404/56813b2f550346895da3fa8f/html5/thumbnails/30.jpg)
Klinefelter’s Syndrome
302n = 47
![Page 31: Mutations](https://reader036.vdocument.in/reader036/viewer/2022070404/56813b2f550346895da3fa8f/html5/thumbnails/31.jpg)
Turner’s Syndrome
312n = 45