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Cystic Fibrosis (CF) - gene location. Cystic Fibrosis (CF): Molecular defect. Cystic Fibrosis (CF): One gene may lead to many phenotypic effects. Cystic Fibrosis lungs. Lung from a CF patient, showing extensive destruction as a result of obstruction and infection. Normal lung. - PowerPoint PPT Presentation
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Cystic Fibrosis (CF) - gene location
Cystic Fibrosis (CF): Molecular defect
Cystic Fibrosis (CF): One gene may lead to many phenotypic effects
Cystic Fibrosis lungs
Normal lung Lung from a CF patient, showing extensive destruction as a result of obstruction and infection
Normal pancreasCF Pancreas showing infiltration of fat and fibrotic lesions
Cystic Fibrosis Pancreas
Tay Sachs
• Defective enzyme that breaks down a particular fatty substance
ALPHA GLOBIN ALPHA GLOBIN
BETA GLOBIN BETA GLOBIN
Sickle cell mutation
Heme
Iron atom
Heme
Iron atom
Sickle cell mutation
9
The hemoglobin tetramer
Normal and Sickled Cell
10
Sickle Cell Anemia (AR)
Aggregation of hemoglobin molecules. Mutant hemoglobin molecules in red cells stack to form rodlike structures, which causes the red cells to deform.
The Genetics of Cancer
Fig. 11-12Signaling cell
DNA
Nucleus
Transcriptionfactor(activated)
Signaling molecule Plasma
membraneReceptorprotein
Relayproteins
TranscriptionmRNANewprotein
Translation
Target cell
2
1
3
4
5
6
Signal Transduction:
How a cell can respond to signals from its environment
Results in a change in which genes are expressed (turned on)
Fig. 11-20aGrowth factor
Protein thatStimulatescell division
Translation
Nucleus
DNA
Target cell
Normal productof ras gene
Receptor
Relayproteins
Transcriptionfactor(activated)
Hyperactiverelay protein(product ofras oncogene)issues signalson its own
Transcription
Ras is an oncogene (cancer gene) the normal form of the gene is called a proto-oncogene
Oncogenes STIMULATE cell division
Fig. 11-18a
Mutation withinthe gene
Hyperactivegrowth-stimulatingprotein in normalamount
Proto-oncogene DNA
Multiple copiesof the gene
Gene moved tonew DNA locus,
under new controls
Oncogene New promoter
Normal growth-stimulatingprotein in excess
Normal growth-stimulatingprotein in excess
Fig. 11-20bGrowth-inhibiting factor
Protein thatinhibitscell division
Translation
Normal productof p53 gene
Receptor
Relayproteins
Transcriptionfactor(activated)
Nonfunctional transcriptionfactor (product of faulty p53tumor-suppressor gene) cannot trigger transcription
Transcription
Protein absent(cell divisionnot inhibited)
Normal tumor-suppressor genes prohibit cell division
Fig. 11-18b
Mutated tumor-suppressor geneTumor-suppressor gene
Defective,nonfunctioningprotein
Normalgrowth-inhibitingprotein
Cell divisionunder control
Cell division notunder control
18
Both alleles of BRCA1 or both alleles of BRCA2 must be mutant for cancer to develop.
Why would in follow a dominant inheritance pattern?
A tissue comprised of billions of cells heterozygous for BRCA1 or BRCA2
20
Your (my) probability of winning the lottery is very small. The probability that someone will win it is very large.