Applications of Genetics

1. Genetic Screening Genetic screening: any procedure used to identify individuals with an increased risk of passing on an inherited disorder. Allows people who would be at high risk of having children with a disorder the choice to not have children, or to screen and abort children with a genetic disorder.

example: screening for PKU early detection with a blood sample allows dietary intervention and prevents or delays symptoms

2. Genetic Counselling Risk groups: pregnant women 35 yrs + parents who have already produced one genetically abnormal child couples from high risk groups for specific diseases

Background Information gathered: nature of problem in question family pedigree results of examination of affected individual look at role of environment in expression of defect results of any lab tests

Value: allows doctors to make recommendations on probability of problem births allows family to control environmental factors that may worsen problem allows family to join support groups to help them cope

3. Prenatal Diagnosis The purpose of prenatal diagnosis is to test the fetus for a genetic problem for which the family is at risk

amniocentesis: weeks into pregnancy a needle is pushed through the abdominal wall amniotic fluid is withdrawn and centrifuged fetal cells in the fluid are isolated and a karyotype is made

chorionic villus: 9 – 12 weeks into pregnancy tube inserted intravaginally cells from chorionic membrane are suctioned out fetal cells are isolated and a karyotype is made

A karyotype is a picture showing all of the chromosomes in an indivdual

4. Recombinant DNA A plasmid is a small circular piece of DNA in a bacteria. A restriction enzyme cuts DNA at a specific sequence of base pairs. The bacteria is the factory, the human gene is placed into the bacteria and the bacteria makes the human protein. The purpose is to produce missing proteins to allow us to treat people with defective genes.

5. Gene Therapy Inserting a working copy of a gene into the cells that lack the ability to produce their own protein. Stem cells are undifferentiated cells (i.e. cells that have not become cells with specific functions such as skin cells or muscle cells). Stem cells are used because replacement genes can be transferred into stem cells, and the stem cells could divide and differentiate to produce more cells with the specific gene. This transfer of genes may actually correct some hereditary defects.

6. The Human Genome Project The HGP was started in 1990 by scientists from about 40 different countries and the first phase was completed in 2002.

About 50% of human DNA is considered to be ‘junk DNA’. The human genome has 30,000 to 35,000 genes and approximately x base pairs. Results: ‘Junk DNA’ is DNA on the human chromosomes that has no apparent purpose.

Cloning involves make exact copies of an original organism The motive is to replicate an exceptional individual, eg. a cow that produces extra volume or quality of milk The clone will be genetically identical, but not necessarily phenotypically identical to the parent. 7. Cloning

example

genetic mother surrogate mother Kitten, not quite identical to genetic mother.

Ethics of Current Practices