1. Single Gene Disorders

2. Turn to your partner… Odds first -tell them everything you know about DNA. Evens second - what can you add on

3. DNA Review
DNA from all organisms is made up of the same pieces The order of A,C,T, and G’s spell out the exact instructions required to create a particular organism with its own unique traits.

4. Small sequence of DNA for making insulin protein
Sequence 1 - Human insulin gene sequence
DNA: C C A T A G C A C G T T A C A A C G T G A A G G T A A
Sequence 2 – Cow insulin gene sequence
DNA: C C G T A G C A T G T T A C A A C G C G A A G G C A C

7. Genes: Your special instructions
Most of our DNA is “junk” DNA= no instructions
The parts of our DNA that do have instructions are called Genes
Genes vary in length
Some contain thousands of base pairs
Some contain millions of base pairs
20,000 human genes have been identified
The instructions in your genes are directions for synthesizing (making) proteins.
GENE

8. Proteins Proteins: -Perform most life's functions (enzymes in
chemical reactions)
-Make up the majority of cellular structures
Proteins are made up of smaller subunits called
____________ (There are 20 amino acids)
A chain of seven amino acids = 1 billion possible combinations
amino acids
Met
Leu
Ser
Leu
Thr
Gly
Ile

9. Human Chromosome Math
How many chromosomes do humans have in every cell of their body (not including gametes)? 46

10. Human Chromosome Math
_________________=chromosomes that have genes in them to make proteins to turn you into a boy or girl _________________= chromosomes with no genes for sex determination _______________ = is a picture of all 46 human chromosomes grouped together in homologous pairs from longest to shortest, with sex chromosomes last
Sex Chromosomes
Autosomes
Karyotype

12. Autosomal?
These types of gene disorders are only found in chromosome pairs 1-22!

13. What is a gene disorder?
The instructions in 1 out of the 20,000 genes gets messed up

14. What is a gene disorder?
Insertion, deletion or substitution of 1 or more bases changes amino acids and makes the protein incorrectly
“Normal” DNA sequence Mutated DNA sequence
DNA: TCACGATTT
DNA: TCATGATTT
mRNA: AGUGCUAAA
mRNA: AGUACUAAA
Ser
Lys
Ser
Ala
Lys
Thr

16. Example: Cystic fibrosis (1 in 2000 Europeans) Gene on chromosome 7 Normal dominant allele (N) makes a protein to transport chloride ions across cells Mutated recessive allele (n) makes a protein that does not transport chloride ions across cell Result= mucus that clogs lungs and pancreas=shortened life expectance to early adulthood NN=normal Nn=normal nn=cystic fibrosis

17. Example: Tay-Sachs disease (1 in 600 Jews)
Gene on chromosome 15
Normal dominant allele (N) makes a protein that is an enzyme which breaks stuff down in lysosome’s
Mutated recessive allele (n) makes an enzyme that does not work
Result= build up of waste causes nerve cells to die= brain damage and death in early childhood
NN=normal Nn=normal nn=Tay-Sachs

18. Example: Sickle cell anemia (1 in 500 African Americans)
Gene on chromosome 11
Normal dominant allele (N) makes a protein that carries oxygen in red blood cells
Mutated recessive allele (n) makes a protein that causes the cell to change shape
Result= Cylinder shaped red blood cells clog blood vessels= damaged organs due to lack of oxygen
NN=normal Nn=Normal nn= sickle cell anemia

20. Example: Huntington’s Disease (1 in 10,000) Gene on chromosome 4
Normal recessive allele (n) makes a protein that helps move vesicles in nerve cells
Mutated dominant allele (N) makes a damaged protein which causes defected nerves in brain
Result=at middle age loss of body function and death
NN=Huntington’s disease Nn=Huntington’s disease
nn= normal