1. Mutations and Chromosomal Disorders

4. Mutation or birth defect?

5. Mutations
Random Accidents/Generally Insignificant or Beneficial or Bad
Accidents- Replications/Transcriptions
Mitosis
Meiosis
Gene Mutation: More Common

6. Do all mutations affect the organisms?
No!
Mutations may occur in a gene that is turned off in a cell (ex. Kidney cell vs. Heart Cell)
When this occurs, there is no affect on the organism!
Example: Concert Sound Board

7. Mutagen Factors in the environment that cause mutations
Can you think of a few?
X-Rays, UV waves, various chemicals

8. Mutations Gene Mutation Chromosome Mutation Substitution Deletion
Point mutation
Deletion
Frame-shift mutation
Addition
Chromosome Mutation
Nondisjunction
Fragmentation
translocation
Inversion
Addition
Deletion
Polyploidy

10. Translocation

11. A mutation can only be passed on to offspring IF
THE MUTATION IS PRESENT IN THE GAMETES / SEX CELLS

12. Gene Mutations Substitution (point mutation)- changes one codon
Deletion (frameshift mutation)- everything changes after the removal of that nucleotide
Same effect in an addition
*more detrimental than substitutions

13. Chromosomal Mutation
Affects the whole chromosome and all genes on chromosomes
Will be more detrimental!
Mutations passed on if occur in sex cells

14. DNA template strand T A C T T C A A A C C G A T T A T G A A G T T T G G C T A A
mRNA A U G A A G U U U G G C U A A
Protein
Met
Lys
Phe
Gly
Stop
Amino end
Carboxyl end
Nucleotide-pair substitution: missense
T instead of C T A C T T C A A A T C G A T T A T G A A G T T T A G C T A A
A instead of G A U G A A G U U U A G C U A A
Met
Lys
Phe
Ser
Stop

15. DNA template strand T A C T T C A A A C C G A T T A T G A A G T T T G
mRNA A U G A A G U U U G G C U A A
Protein
Met
Lys
Phe
Gly
Stop
Amino end
Carboxyl end
Nucleotide-pair deletion: frameshift causing extensive missense A
missing T A C T T C A A C C G A T T A T G A A G T T G G C T A A U
missing A U G A A G U U G G C U A A
Met
Lys
Leu
Ala

16. Nondisjunction
Chromosomes that normally separate during Meiosis stay together and can cause several genetic disorders in humans
Examples: Down Syndrome, Turner’s, Klinefelter’s

17. Down’s Syndrome
-extra copy of
chromosome # 21
Turner’s Syndrome
-underdeveloped sexual
characteristics
-webbed neck

18. Klinefelter’s Syndrome
-two X chromosomes
and a Y
-male with underdeveloped sex organs

19. Polyploidy Cells have some multiple of the normal chromosome number
Example: Plants with Polyploidy are usually larger with larger fruit

20. Polygenetics Polygenic Trait- traits controlled by many genes
(examples  height, skin color, eye color)

21. Genetic Screening
When a person’s genetic make-up is analyzed to determine the possibility of genetic disorders for themselves and that could be passed on to future offspring

22. Common Genetic Disorders

23. Sex-linked Disorders
Hemophilia
Color-Blindness
Male Pattern Baldness

24. Autosomal Disorders Sickle Cell- sickle shaped blood cells
Tay –Sachs-death by the age of 4
Cannot breakdown lipids in the brain
PKU-Caused by mutation and cannot break down phenylalanine
Cystic Fibrosis-(refer to video on Active Transport) Missing gene to control formation of mucus
Huntington’s Disease-fatal but do not appear until 30 years old-due to breakdown of the brain cells
Pompe Disease- caused by mutation in the GAA gene (leads to excessive build up of glycogen in muscle cells)

25. Detecting Genetic Disorders
Karyotyping
Amniocentesis
Chorionic villus sampling
Ultrasound

26. Karyotype: Normal

27. Karyotype: Edward’s Syndrome

28. Edward’s Syndrome

29. Amniocentesis (Ultrasound)

30. Amniocentesis

31. Amniocentesis

32. Ultrasound

34. Genetic Engineering

35. Definition
The process of producing altered DNA, usually by breaking a DNA molecule and inserting new genes

36. Recombinant DNA (Gene Splicing)
DNA from two different species is joined together
Provides a way of producing large amounts of sometimes rare substances
Example: Insulin and clotting factors that treat Hemophilia
What is used to cut DNA? (Hint: Electrophoresis)
Restriction Enzymes

37. Gene Therapy
The process of correcting genetic defects by transferring normal genes to cells that have defective genes
Sometimes normal genes are introduced to the cell by means of virus or bacteria
Used in both Plants and Animals