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http://www.youtube.com/watch?v=gO1GiRKmEqs. Transposons. “Jumping genes”. Function Other proteins 10%. Retrotransposons. RNA Intermediate DNA Reverse transcriptase enzyme. Repetitive DNA. Nucleotide Sequence. Tandemly repetitive DNA – 10-15% short Satellite DNA
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Transposons “Jumping genes” • Function • Other proteins • 10% Retrotransposons • RNA Intermediate • DNA • Reverse transcriptase enzyme
Repetitive DNA Nucleotide Sequence • Tandemly repetitive DNA – • 10-15% • short • Satellite DNA • Genetic disorders (triplets) • Interspersed repetitive DNA – • 25-40% • Long • Scattered • Similar • 10-1 million • Alu Elements • Regular Satellite DNA – • 10,000-1 million times • Telomeres and centromeres • Minisatellite DNA – • 10-10,000 times • Microsatellite DNA – • Fingerprints • 1-10 times
Gene Amplification Selective replication Cancer cells Example: Developing ovum More ribosomes Later broken down Also selective loss of genes • Insects
Multigene Family Collection of similar genes • Repetitive DNA • Example: hemoglobin • Pseudogenes
Immunoglobulin Genes • Cell differentiation • identify viruses and bacteria • Many rearragnements • Binds to epitope on antigen
5 Words of Review • Enzymes (genes and coding) • Dehydration Synthesis (retrotransposons) • Disulfide Bridges (antibody molecules) • Evolution (multigene families) • Photorespiration (useless like pseudogenes)
Review Questions • What are the two types of repetitive DNA and what is the difference between the two? • What is the purpose of gene amplification and one example? • What is a multigene family? • What causes multigene families?
Review Questions • What is the basic structure of immunoglobulin genes? • What is done to the gene that specifies it as an immunoglobin gene? • How can transposons change the function of different genes? • What is a sequence of DNA that seems to code for a protein but is lacking something that causes that certain gene to be expressed?