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Mutations

Mutations. What is a mutation?. Changes in the DNA sequence that affect genetic information. Gene Mutations. Result from changes in a single gene . 3 Types: Substitution Insertion (Frame-shift) Deletion (Frame-shift). Point Mutations. Substitution One nucleotide replaces another.

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Mutations

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  1. Mutations

  2. What is a mutation? • Changes in the DNA sequence that affect genetic information.

  3. Gene Mutations • Result from changes in a single gene. • 3 Types: • Substitution • Insertion (Frame-shift) • Deletion (Frame-shift)

  4. Point Mutations • Substitution • One nucleotide replaces another. • Usually changes one amino acid in the sequence of the protein. • Ex: sickle cell anemia

  5. Point Mutation (Substitution)

  6. Frame Shift Mutations • Insertion/Deletion • Insertion - the addition of a nucleotide. • Deletion - the removal of a nucleotide. • Bases are still read in groups of three (codons). • Changes many amino acids in the sequence of the protein

  7. Frame Shift Mutation (Insertion)

  8. Frame Shift Mutation (Deletion)

  9. Which would you rather have?

  10. What Causes Mutations? • May occur spontaneously during cell division/meiosis. • X-rays • Asbestos • Insecticides • UV light • Radioactive substances

  11. How Are Mutations Passed On? • The mutation must happen in a sex cell (gamete).

  12. Chromosomal Mutations • Involve changes in whole chromosomes. • chromosomal mutations • 5 types: 1. Translocation 2. Duplication 3. Deletion 4. Inversion 5. Nondisjunction

  13. Chromosomal MutationsDeletion, Inversion, Translocation, Duplication https://www.youtube.com/watch?v=FgMKGIED4Yo

  14. Chromosomal Mutations https://www.youtube.com/watch?v=FgMKGIED4Yo

  15. Nondisjunction • An error that occurs during meiosis in which homologous chromosomes fail to separate properly. • One gamete may receive two of the same type of chromosome and another gamete receives no copy. • Ex- down syndrome

  16. Down Syndrome (Trisomy 21) • Trisomy:having three copies of one chromosome. • Down Syndrome is caused by a trisomy on the 21st chromosome. • Likelihood of this disorder increases with the increasing age of the mother.

  17. Age of Mother vs. Down Syndrome

  18. Ways to Detect Genetic Disorders • Karyotyping- prepared enlarged photograph showing paired homologous chromosomes from a cell. • May show chromosomal abnormalities such as an extra or missing chromosome.

  19. Testing for Down Syndrome https://www.youtube.com/watch?v=Ju-q4OnBtNU http://www.bmhvt.org/healthmatters/pros-and-cons-of-genetic-screening-during-pregnancy What are your thoughts on Down Syndrome testing? Would could the mother do?

  20. Medical Genetic Research • Generates knowledge used to design ways of diagnosing, preventing, treating, controlling, or curing diseases of plants and animals.

  21. Genetic Counseling • Discussions between physician and the family which may include inheritance patterns, prediction of genetic disorders, and family planning. • Screening • Karyotyping • Amniocentesis

  22. Screening • Chemical analysis of body fluids such as blood and urine. Analysis may indicate the presence of chemicals associated with genetically-related disorders.

  23. Amniocentesis • Involves the removal of amniotic fluid for chemical analysis. • This technique can show the chromosome content of the cells of the embryo.

  24. Amniocentesis https://www.youtube.com/watch?v=bZcGpjyOXt0

  25. Genetic Disorders • PKU (Phenylketonuria): individuals lack the enzyme that is needed to break down phenylalanine. • If a newborn has PKU, phenylalanine may build up in the tissues during the child’s first years of life and cause severe mental retardation. • https://www.youtube.com/watch?v=XKSoMi4U-1k

  26. Genetic Disorders: PKU

  27. Genetic Disorders • Tay-Sachs Disease: lipid accumulation in the brain cells, mental deficiency, blindness, death in early childhood. • https://www.youtube.com/watch?v=RzEpkBU-ITA

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