ch24
TRANSCRIPT
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