HUMAN MOLECULAR GENETICS

Lecture 14-3

Genetic testing

• Genetic tests are now available for hundreds of disorders.

• Parents can find out if they carry defective recessive genes can be passed to their children.

Mail order genetic testing, England

DNA fingerprinting

1. sample of DNA is cut with enzymes 2. each person has a different length of DNA

between genes (repeats) 3. fragments are separated by size using gel

electrophoresis 4. repeats are ‘tagged’ with radiation, then x-rayed

Identifies criminals & victims of crimes since 1980s

Samples can be from blood, hair follicles, or sperm

Each person’s pattern is unique.

The Human Genome Project An ongoing effort

to analyze the human DNA sequence.

Computers look for genes by finding the sites (promoters) where RNA polymerase binds to DNA before making mRNA.

results

Only a small part of DNA holds genes

Humans: 25,000 All the

information is available to anyone on the internet

Will lead to further discoveries

Gene therapy

An absent or faulty gene is replaced by a normal, working gene

Goal: to cure genetic diseases by changing the genes that cause them.

• .

A genetically altered virus is inhaled to treat cystic fibrosis

• Method: use a genetically altered virus to deliver the functioning gene to the cells

• Possible treatment for ALD, hemophilia.

• Still in experimental stages.

Ethical issues in human genetics

• If genes can be used to change a person, where should it stop?

• Should humans be designed?

• It is the responsibility of all people to be sure that science is used wisely and ethically.

Logo of the human genome project