Lecture 7 Gene Structure and Transposable Elements Gene structure Gene families
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Transcript of Lecture 7 Gene Structure and Transposable Elements Gene structure Gene families
Lecture 7
Gene Structure and Transposable Elements
Gene structure
Gene families
Repetitive DNA including transposons
Organelle genomes
Reading: Chapter 10
Molecular Biology syllabus web site
Gene Structure
Gene Families-tissue-specific and temporal-specific expression
-diverging activities or localization
DNA Classes
Reassociation experiments reveal three major fractions of eukaryotic DNA
• Single copy DNA (50-60%)
• Moderately-repeated/ intermediate-repeat DNA (25-40%); includes mobile DNA elements
• Simple-sequence DNA (10-15%)
Human metaphase chromosomes: in situ hybridization with fluorescent-labelled “simple
sequence” DNA probe
Human DNA fingerprints
DNA probed with 3 different microsatellite DNA probes a,b,c show characteristic patterns of individuals.
Probe ‘b’
Mutable phenotypes caused by transposable elements
nonmutable
mutable
Transposable Elements
Transposable element excision results in target site duplication or other DNA sequence changes
Chromatin Structure
Nucleosomes
DNA
DNA
Cultured undifferentiated MSB cellsDifferentiated red blood cells at 14 days
Chromatin structure changes during differentiation of cells