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PowerPoint® Lecture Presentation for Concepts of Genetics Ninth Edition Klug, Cummings, Spencer, Palladino Chapter 9 Extranuclear Inheritance Lectures by David Kass with contributions from John C. Osterman. Copyright © 2009©Pearson Education, Inc. Copyright 2009 Pearson Education, Inc. Examples of Extranuclear Inheritance • Organelle heredity • Infectious heredity • Maternal effect Copyright © 2009 Pearson Education, Inc. Section 9.2 • Chloroplast DNA (cpDNA) • Ranges from 100 to 225 kb in length, and the genes carried on the DNA encode products involved in photosynthesis and translation. • Circular, doublestranded DNA Copyright © 2009 Pearson Education, Inc. Chloroplast Copyright © 2009 Pearson Education, Inc. Section 9.2 • Mitochondrial DNA (mtDNA) • Circular, double-stranded DNA • is smaller than the DNA in chloroplasts, and introns are absent. • Most of the protein encoding genes are located on a single strand. • The contribution of nuclear and mitochondrial gene products is shown in Figure 9.8. Copyright © 2009 Pearson Education, Inc. Mitochondrion Copyright © 2009 Pearson Education, Inc. Copyright © 2009 Pearson Education, Inc. Figure 9.8 Endosymbiotic Theory http://thebrain.mcgill.ca/flash/a/a_05/a_05_cl/a_05_cl_her/a_05_cl_her_1b.jpg Copyright © 2009 Pearson Education, Inc. Section 9.1 • Inheritance of chloroplast or mitochondrial traits is often determined by the phenotype of the ovule source (Figure 9.1). Copyright © 2009 Pearson Education, Inc. Four O’Clock Plants Copyright © 2009 Pearson Education, Inc. Figure 9.1 Section 9.1 • Chlamydomonas is an excellent model system for studying organelle heredity because it has a single large chloroplast that exhibits a uniparental inheritance pattern. Copyright © 2009 Pearson Education, Inc. Mitochondrion Heteroplasmy http://www.bio.miami.edu/dana/104/mitochondrion.jpg Copyright © 2009 Pearson Education, Inc. Section 9.3 • For a human disorder to be attributed to mitochondrial DNA: • the inheritance must exhibit a maternal inheritance pattern • the disorder must reflect a deficiency in the bioenergetic function of the organelle • there must be a specific mutation in a mitochondrial gene Copyright © 2009 Pearson Education, Inc. Section 9.3 • Three disorders arising from mtDNA are: • myoclonic epilepsy and ragged red fiber disease (MERRF) • Leber’s hereditary optic neuropathy (LHON) • Kearns–Sayre syndrome (KSS) Copyright © 2009 Pearson Education, Inc. MERRF MERRF Cells Normal Skeletal Muscle. Crosssection. http://img.medscape.com/pi/emed/ckb/neurology/11348151189245-1189246-1189490.jpg Copyright © 2009 Pearson Education, Inc. 9.5 In Maternal Effect, the Maternal Genotype Has a Strong Influence during Early Development Copyright © 2009 Pearson Education, Inc. Copyright © 2009 Pearson Education, Inc. Figure 9.12 Copyright © 2009 Pearson Education, Inc. Figure 9.13 The End Copyright © 2009 Pearson Education, Inc.