L11 Bizarre Deviants Pt2

L11 Bizarre - http/www.willowaynurseries.com/Images/EuonymusGoldSplash Bizarre Deviants Pt 2 Epigenetics and Extranuclear inheritance 1 Bizarre

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Unformatted text preview: http://www.willowaynurseries.com/Images/EuonymusGoldSplash.jpg Bizarre Deviants Pt. 2 Epigenetics and Extranuclear inheritance 1 Bizarre deviants! Pt1 The Maternal Effect Genetic examples Molecular basis for inheritance Maternal effect in flies Epigenetic Inheritance Dosage compensation Molecular basis for dosage compensation 2 Genes on inactive X are not completely ‘off’ pseudoautosomal genes: Located on both Y and X Regions of homology and where sex chromosomes pair during meiosis genes here are always active active inactive 3 Bizarre deviants! Pt2 Epigenetic inheritance Genomic imprinting Examples in human disease Extranuclear inheritance Inheritance patterns Examples in human disease Endosymbiotic Theory: chloroplasts and mitochondria 4 Epigenetic inheritance: genomic imprinting only 1 allele is expressed (for example, only the maternal allele) in the offspring 5 Case Study: Igf2 in mice Igf2 = normal allele - = dwarf allele Igf2 Igf2/Igf2- Igf2/Igf2- same genotype, different phenotype!! Dwarf Normal phenotype phenotype 6 Case Study: Igf2 in mice Mother’s Father’s genotype X genotype Igf2-/Igf2Igf2/Igf2 Mother’s Father’s genotype X genotype -/Igf2Igf2/Igf2 Igf2 wt alleles in bold 7 The imprint is ‘reset’ with each generation Igf2/Igf2normal Igf2/Igf2normal both of these alleles are shut down both of these alleles are active 8 How is a gene ‘shut down’? CH3 CH3 CH3 CH3 DMR Igf2 differentially methylated region (2006) Shirley M. Taylor Cellscience Reviews Vol.2 No.3 9 How is Igf2 shut down in mother? CH3 CH3 CH3 10 The reset button is pushed in gametes all mom’s eggs - no CH3 all dad’s sperm - CH3 11 Human disease resulting from genomic imprinting Prader-Willi Syndrome (PWS) results from deletion in dad’s chromosome 15 Angelman Syndrome (AS) results from deletion in mom’s chromosome 15 http://www.aafp.org/afp/20050901/827.html http://www.psychnet-uk.com/dsm_iv/pictures/angel.jpg 12 Both diseases result from deletion in chromosome 15 x mom dad x mom dad AS PWS 13 Extranuclear inheritance http://it.pinellas.k12.fl.us/Teachers5/thomasa/images/ACFE240210314D35B0A80F99CDAD923D.jpg 14 mtDNA and cpDNA Chloroplast nucleoid Mitochondria nucleoid 15 Formation of endosymbionts 16 Mt and cp share numerous features with prokaryotic cells compare to mitochondria Respiratory membrane Thylakoid membranes compare to chloroplast Aerobic prokaryote http://img.search.com/thumb/e/eb/Diagram_of_a_human_mitochondrion.svg/622px-Diagram_of_a_human_mitochondrion.svg.png Photosynthetic prokaryote 17 Solar powered sea slugs! http://www.seaslugforum.net/ 18 mtDNA in humans 19 cpDNA in plants 20 The maternal inheritance pattern all white offspring all green offspring 21 Inheritance patterns mtDNA mutations http://www.neurocast.com/site/images/02_2002/pedigree.gif 22 Mechanism Chloroplasts and mitochondria are present in egg cells, but not in sperm (usually) Inheritance of cpDNA and/or mtDNA is through maternal line http://chinesemedicinenews.com/wp-content/uploads/2007/07/egg-and-sperm.jpg 23 Human disease affected by mitochondrial mutations Leigh’s Disease Also implicated in: Alzheimer’s, Parkinson’s and Huntington’s magaretconnors.com/ 24 Summary Epigenetic inheritance: Genomic imprinting - only one allele (from either mom or dad, depending on gene) is expressed AS (inherited from mom) and PWS (inherited from dad) both result from a deletion on chromosome 15 Extranuclear inheritance: Usually maternally inherited chloroplast / mitochodrial DNA Mutations in mtDNA affect ATP production Endosymbiotic Theory: the evolution of chloroplasts and mitochondria in eukaryotes 25 Ungraded problems Go through Chapter 7 S3 Try Chapter 7 C5, C20, C24, C35 26 Next Time Review for Exam 1 http://i.ehow.com/images/GlobalPhoto/Articles/2148399/studying-main_Full. 27 ...
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This note was uploaded on 03/29/2009 for the course BIO 325 taught by Professor Saxena during the Fall '08 term at University of Texas at Austin.

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