1. Lecture 7 Gene Structure and Transposable Elements Gene structure Gene families Repetitive DNA including transposons Organelle genomes Reading: Chapter 10 Molecular Biology syllabus web siteweb site

4. Gene Structure

6. Gene Families -tissue-specific and temporal-specific expression -diverging activities or localization

7. DNA Classes

8. 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%)

9. Human metaphase chromosomes: in situ hybridization with fluorescent-labelled “simple sequence” DNA probe

11. Human DNA fingerprints DNA probed with 3 different microsatellite DNA probes a,b,c show characteristic patterns of individuals. Probe ‘b’

12. Mutable phenotypes caused by transposable elements nonmutable mutable

13. Transposable Elements

15. Transposable element excision results in target site duplication or other DNA sequence changes

20. Chromatin Structure

22. Nucleosomes DNA

24. Cultured undifferentiated MSB cellsDifferentiated red blood cells at 14 days Chromatin structure changes during differentiation of cells