1. DNA Mutations & Disorders

2. Adermotoglyphia- mutations on gene SMARCAD1

3. Normal Protein Formation
A segment of DNA strand is copied by mRNA in the nucleus.
mRNA leaves nucleus and goes to ribosome in cytoplasm.
Ribosome “reads” mRNA and calls for specific amino acids.
Amino acids linked together to form protein chain.

4. Mutations in DNA will code for wrong amino acids which will cause wrong protein to form.
Can lead to cell death, disease, disorders

5. What is a mutation? Any change in a gene or chromosome.
Most are natural and have no effect on the organism- can promote good genetic diversity
Some are harmful
Some are lethal (cause death in offspring)
Some are good for the organism (ex: some mosquitoes have a gene mutation that makes them resistant to pesticide- leads to evolution of stronger mosquito populations)

8. What are some types of mutations?
Point mutation- change in ONE single nitrogen base in ONE gene.
This change causes the code to change so amino acids are not put in correct order.
EX: albinism, sickle cell anemia

9. Types of Point Mutations
A. Silent- one letter change but no change in amino acid= no change in protein structure= no problems
B. Missense- one letter change causes changed amino acid= wrong protein structure
C. Nonsense- one letter change causes STOP codon in middle of amino acid chain= protein won’t get made
(Normal)

10. What are some types of mutations?
2. Chromosome Mutations (Frameshift)- changes in MANY genes, entire segments of chromosome are messed up.
Because more genes are involved, usually more harmful to the organism.

11. Types of chromosome mutations
Deletion- part of chromosome is lost
Duplication- part of chromosome is repeated twice
Inversion- chromosome breaks, piece is turned over & reinserted upside down
Translocation- two chromosomes affected- one piece detaches & reattaches to another chromosome A B C D

12. Types of chromosome mutations Cont…
E. Insertion- a nitrogen base is added which causes nitrogen bases to shift to the right, throws off amino acid sequence.
F. Nondisjunction- a chromosome pair fails to separate properly during meiosis (some sperm/egg get too many chromosomes, some get too few).
Monosomy- too few (45 chromosomes)
Trisomy- too many (47 chromosomes)

13. What are some causes of mutations?
1. Mutagen- anything that causes a mutation in DNA in a cell.
UV light
Radiation
X rays
chemicals in tobacco smoke, synthetic materials, pollution
viruses

14. What is the difference between germ cell mutation & somatic cell mutation?
Occurs in gametes (sperm/egg)
Does not affect individual person
CAN be passed to offspring
Somatic Cell mutation
Occurs in body cells
Affects individual in which it occurs
CANNOT be passed to offspring
If occurs in genes that control cell reproduction can become CANCER.

15. What are some methods of detection?
Ultrasound- sound waves generate image of unborn child. Detect abnormalities of limbs, organs, etc.

16. What are some methods of detection?
Amniocentesis: use needle to extract fluid/cells surrounding the fetus. Chromosomes can then be karyotyped

17. What are some methods of detection?
Karyotyping: pictures of chromosomes are matched up according to size