1. The New Genetics Part II

2. Studying the genetics of human is more difficult than peas or fruit flies because-
1. Generation time is years instead of weeks
2. It is unethical to use humans in breeding experiments.
Use of pedigrees and studies of identical twins can help in study human genetics.

3. Human genetic disorders fall into three categories-
1. Disorder caused by a single trait that follows Mendelian genetics (4000 discovered)
2. Large scale chromosomal disorders (trisomy, translocation etc.)

4. 3. Multfactorial disorders that are controlled by several genes (heart disease, spina bifida, diabetes, certain cancers etc)
The highest incidence is #3.
The most common #1 in Caucasians is cyctic fibrosis. 1/20 carry this gene.

5. Disorder Frequency/1000
Autosomal Dominant
Autosomal Recessive
X-linked recessive
Chromosome Abnorm
Multifactorial
Unknown origin 1.2

6. Some recessive genetic disorders produce an nonfunctional enzyme for a particular biochemical pathway. i.e. PKU which is missing an enzyme which converts phenylalanine to tyrosine. This causes the build up of phenyalanine. Treatment is a diet low in phenylalanine
Without the diet, children become severly retarded, have seizures.
Sickle cell anemia is a simple case of a point mutation.

7. Prenatal diagnosing
Amniocentesis-removal a some fetal cells from the amniotic sac. Cells are cultured and grown for several weeks then there is biochemical analysis for any metabolic disorders such as Tays-Sachs. The cells are also karyotyped for any chromosomal abnormalities such as Down Syndrome

9. Choronic villi sampling (CVS) in the 8-10 week of sampling a few cells are removed from the chorion or fetal membrane. This is faster because cells are growning.

10. Ultrasound-Uses high frequency vibrations to produce an image on a TV screen. Can detect enlarged or absent kidneys, some heart defects, neural tube disorders and others.

11. Treatment for genetic disorders
1. Modifying an individual’s environment or lifestyle i.e. PKU and high chloresteral
2. Drug therapy which includes enzymes or hormones. i.e. Midgets receiving growth hormone or diabetics receiving insulin hormone.
3. Gene therapy to correct a defect.
Future-
Identifying defective genes and gene therapy- being able to correct a defective gene

12. Genetic engineering-is the process of man manipulating genes and introducing them into various cells (recombinant DNA).
Tools-
Plasmids from bacterial cells can be extracted and then manipulated and then other cells can take them up.

13. Restriction enzymes- enzymes found in prokaryotic cells that cleave DNA at very specific sites.

14. 1. Every different restriction enzyme (Eco R1 vs
1. Every different restriction enzyme (Eco R1 vs. Hind) cuts the DNA at a different locations or restriction sites.
2. The restriction enzymes will cuts the DNA at every place there is a restriction site.
3. The restriction enzymes can be used over and over again.

18. Electrophoresis uses an electric charge put across an agarose matrix to seperate molecules that have a charge like proteins and pieces of DNA

19. 1. DNA will run toward the positive pole
1. DNA will run toward the positive pole. Smaller pieces (smaller mass) of DNA will run faster to the positive pole.
2. Proteins will migrate to either the positive or negative pole based on their isoelectric point.
Ligase- enzyme used to bond the DNA back together again

20. This is a protein gel that is running proteins extracted from corn
This is a protein gel that is running proteins extracted from corn. It demonstrates that proteins have either a positive charge or a negative charge.

21. This is a DNA gel that is running viral DNA
This is a DNA gel that is running viral DNA. Lane 1 has not been cut with any enzymes. Lane 2 has been cut with E.CoR1. Lane 3 and 4 has been cut with BOTH EcoR1 and BamH1. Notice how many bands are in each lane.

22. Ligase- enzyme used to bond the DNA back together again