武汉大学：《遗传学》课程教学课件（英文讲稿）Chapter 14 Organellar Genetics

Chapter 14Organellar Genetics16-1

Copyright © The McGraw-Hill Companies, Inc. Permission required to reproduce or display 16-1 Organellar Organellar Genetics Genetics Chapter 14 Chapter 14

Sectionsto study14.1Mitochondria andtheirgenomes14.2Chloroplastsandtheirgenomes14.3 The relationship between organellar and nuclear genomes14.4 Non-Mendelian inheritance of mitochondria andchloroplasts14.5 Mutant mitochondria and human disease16-2

Copyright © The McGraw-Hill Companies, Inc. Permission required to reproduce or display 16-2 Sections to study Sections to study 14.1 Mitochondria and their genomes 14.2 Chloroplasts and their genomes 14.3 The relationship between organellar and nuclear genomes 14.4 Non-Mendelian inheritance of mitochondria and chloroplasts 14.5 Mutant mitochondria and human disease

14.1 Mitochondria and theirgenomesMitochondria are sites of energy productionPresentineukaryotesNumber of mitochondria ineachcell variesOutermembraneTEMInnermembraneCristaMatrix1μmRibosomesCaotiohtoaooePersonEdu16-3

Copyright © The McGraw-Hill Companies, Inc. Permission required to reproduce or display 16-3 Mitochondria are sites of energy production. Mitochondria are sites of energy production.  Present in eukaryotes.  Number of mitochondria in each cell varies. 14.1 Mitochondria and their genomes

OuterInnermembranemembraneCristaeProduce ATPthrough the oxidativeHHHphosphorylation ofADP.MatrixIntermembranePorespaceEnzymesofKrebscycleEnzymesofMatrixelectrontransportchainEnzymesforATPIntermembranesynthesisspaceInnermembraneFig 14.216-4

Fig 14.2 Copyright © The McGraw-Hill Companies, Inc. Permission required to reproduce or display 16-4  Produce ATP through the oxidative phosphorylation of ADP

Thegenomes of mitochondriaMitochondrionTRNAS吉子HtRNAS10-20proteinstRNASmtDNAproteinsShape: circular in most species; linear in a few species.mtDNA lies withinmatrix of the organellein structures callednucleoids.Number of mtDNA ineachmitochondria canchangeReplicationisindependent of the cell cycleand occursrandomly.16-5

Copyright © The McGraw-Hill Companies, Inc. Permission required to reproduce or display 16-5 The genomes of mitochondria The genomes of mitochondria  Shape: circular in most species; linear in a few species. Shape: circular in most species; linear in a few species.  mtDNA lies within matrix of the lies within matrix of the organelle in structures called organelle in structures called nucleoids nucleoids.  Number of Number of mtDNA in each mitochondria can change. in each mitochondria can change.  Replication is independent of the cell cycle and occurs Replication is independent of the cell cycle and occurs randomly. randomly

The size and gene content of mtDNA vary fromorganismtoorganismTABLE16.1Mitochondrial DNA SizesSize (kb)Size:6-2400 kb.Organism6PlasmodiumYeast75Drosophila18110PeaHuman16.5Comparisonof SomeFunctions Encoded inmtDNATABLE16.2OrganismOxidativePhosphorylationGenestRNASGenomeSize(kb)775Yeast251429Marchantia(liverwort)186.0132216.5Human16-6

Copyright © The McGraw-Hill Companies, Inc. Permission required to reproduce or display 16-6 The size and gene content of The size and gene content of mtDNA vary from vary from organism to organism organism to organism Size: 6 Size: 6 - 2400 kb. 2400 kb

Human mtDNA carries closely packed genes(a)SmalribosomalRNA37genesemtrnLargeribosomal RNA13encodepolypeptide1CYTDsubunits that make upNAD1Poxidativephosphorylationatnapparatus"tmatrmNAD6tmeNAD522tRNAgenesNAD2Human2genes for largeand smallmtDNAotmrRNAs(16.5kb)Compact gene arrangementtmtrCOXNointronsNAD4Genes abut or slightly overlapCOXIINAD4LtrnATP6nNAD3ATPSCOXIIIFig14.316-7

Copyright © The McGraw-Hill Companies, Inc. Permission required to reproduce or display 16-7 Human mtDNA carries closely packed genes carries closely packed genes  37 genes 37 genes  13 encode polypeptide 13 encode polypeptide subunits that make up subunits that make up oxidative oxidative phosphorylation phosphorylation apparatus apparatus  22 tRNA genes  2 genes for large and small 2 genes for large and small rRNAs  Compact gene arrangement Compact gene arrangement  No introns introns  Genes abut or slightly overlap. Genes abut or slightly overlap. Fig 14.3

Yeast mtDNA contains spacers and intronsFour times longerrtrnthanhuman mtDNAoirnatrnrpsotrrOtrnLargetrnewnrnLong intergenicatrnribosomaletrnRNAtrnsequences calledATP9COXIspacers separategenesRF2CYTbaccounting for moretrneotrnotrnYeastthanhalf of DNA-COXImtDNAetrn(75kb)Intronsform aboutrn.bo25%ofmtDNA.9SRNAENS2ATP6SmallCOXIATPnibosomalRNAtrn16-8

Copyright © The McGraw-Hill Companies, Inc. Permission required to reproduce or display 16-8 Yeast mtDNA contains spacers and contains spacers and introns introns  Four times longer Four times longer than human than human mtDNA.  Long intergenic intergenic sequences called sequences called spacers spacers separate genes separate genes accounting for more accounting for more than half of DNA. than half of DNA.  Introns Introns form about form about 25% of mtDNA

Unusually organized mtDNAs of protozoan parasites of thegenera Trypanosoma, Leishmania, and CrithidiaProtozoan parasites containGolgibodya singlemitochondrioncalledkinetoplast（动基体）NucleusEKinetoplast16-9

Copyright © The McGraw-Hill Companies, Inc. Permission required to reproduce or display 16-9  Protozoan parasites contain Protozoan parasites contain a single mitochondrion a single mitochondrion called kinetoplast kinetoplast (动基体). Unusually organized Unusually organized mtDNAs of protozoan parasites of the of protozoan parasites of the genera Trypanosoma Trypanosoma, Leishmania Leishmania, and Crithidia Crithidia

Protozoan parasites of the genera Trypanosoma (锥虫),Leishmania（利什曼原虫），andCrithidia（短膜虫）T.b.gambienseTrypanosomiasisNoriskAtriskTrypanosomes in the bloodEndemicHighendemicEpidemicT.b.rhodesienseTsetseflyAfricansleepingsickness16-10

Copyright © The McGraw-Hill Companies, Inc. Permission required to reproduce or display 16-10 Protozoan parasites of the genera Protozoan parasites of the genera Trypanosoma Trypanosoma (锥虫), Leishmania Leishmania (利什曼原虫), and Crithidia Crithidia (短膜虫) Trypanosomes in the blood Tsetse fly African sleeping sickness