ch24

The New Science of Life

Chapter 24

Great Idea:Our new understanding of genetic mechanisms is leading to enormous

technological advances in medicine and other aspects of our lives.

Chapter Outline

• The Technology of Genes• Stem Cells, Cloning, and Regenerative Medicine

• The New Face of Medicine• Unraveling the Past: Mitochondrial DNA

The Technology of Genes

Genetic Engineering

• Genetic engineering– Foreign genes inserted– Existing genes altered

• Technique– Restriction enzymes cut DNA– Another DNA strand binds– New gene is expressed

Genetic Engineering – cont.

• Examples– Insulin– Agriculture

• GMO– DOA– FDA– EPA

• Bioterrorism

Restriction Enzymes

The Process of Genetic Engineering

Genetically Modified Organisms

Technology

• Bioterrorism– Anthrax

•Spores

– Smallpox– Spanish influenza – 1918– Department of Homeland Security

Technology

• The PCR process

Science by the Numbers

• PCR multiplication– Each cycle doubles the number of DNA molecules

DNA Fingerprinting

• DNA fingerprinting– Analysis of DNA in human tissue– Uses

•Identify criminals •Identify victims

• Process– Analyze DNA sections for repeats– Compare to individual of interest

• VNTR• STR

CSI

STR Method of DNA Fingerprinting

Stem Cells, Cloning, and Regenerative Medicine

Stem Cells, Cloning, and Regenerative Medicine

• Gene Control– Genes on or off– Produce only copies

• Early development– Pluripotent

•Develop into any cell in body

Stem Cells, Cloning, and Regenerative Medicine – cont.

• Development– Blastocyst

•Outer cells: placenta•Inner cells: embryonic stem cells

– Gastrula •Not pluripotent•Differentiation

– Adulthood•Somatic or adult stem cells

• Stem cell line – Reproduce without differentiation

Early Stages of Embryonic Development

Science in the Making

• Cloning Dolly the sheep– 1997; Ian Wilmut– Reproductive cloning

•Procedure

– Other mammals cloned

The First Cloned Mammal

Ian Wilmut

Foreign DNA Introduced into an Animal Cell

The New Face of Medicine

Computer-Assisted Drug Design

• Medicine– One or more molecules– Bond to specific molecules– Change cellular chemistry

• Research– Previous

•Search in nature

– Current•Use molecular techniques•Design drugs from scratch

Computer-Assisted Drug Design – cont.

• CADD– Example

•Protease inhibitors

Computer-Aided Drug Design

Cancer-A Different Kind of Genetic Disease

• Normal Cell– Guardianship

• Cancer– Cells reproduce without restraint

•Due to genetic defect•Usually 5–6 damaged genes

– Collection of diseases

Cancer-A Different Kind of Genetic Disease – cont.

• Genetic defects– Increase cancer probability– Lifetime risk >80%

• Cure– Surgery, radiation, chemotherapy– Gene therapy

Normal and Cancer Cells

Science by the Numbers

• Double-blind clinical trials– Judges drug’s effectiveness

Gene Therapy

• Gene therapy– Replace defective gene with healthy– In vivo or in vitro

• Example– SCID

• Problems– Genes inserted randomly– No proteins made

• Therapeutic viruses

Gene Therapy Process for SCID

DNA Repair in the Cell

• Damage– Outside cell

•Human developed•Nature

– Inside cell

DNA Repair in the Cell – cont.

• Repair mechanisms– Point defect

•Enzymes remove section

– Mismatch •Remove length of DNA•Reconstruct section

DNA Repair in a Cell

Plants and Pesticides

Unraveling the Past:Mitochondrial DNA

Unraveling the Past:Mitochondrial DNA

• Mitochondria– Independent DNA (mtDNA)– Single loop– 37 genes– Non-coding section

•1000 base pairs•Use to study human evolution

– All mitochondria from mother

DNA in Mitochondria

Thinking More about Embryonic Stem Cells

• Issue debated• No simple answers