Einführung in die Genetik

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1 Einführung in die Genetik Prof. Dr. Kay Schneitz (EBio Pflanzen) #genetiktum FB: Plant Development TUM Prof. Dr. Claus Schwechheimer (PlaSysBiol)

2 Einführung in die Genetik - Inhalte 1 Einführung KS 2 Struktur von Genen und Chromosomen KS 3 Genfunktion KS 4 Transmission der DNA während der Zellteilung KS 5 Vererbung von Einzelgenveränderungen KS 6 Genetische Rekombination (Eukaryonten) KS 7 Genetische Rekombination (Bakterien/Viren) KS 8 Rekombinante DNA-Technologie CS 9 Kartierung/Charakterisierung ganzer Genome CS 10 Genmutationen: Ursache und Reparatur CS 11 Regulation der Genexpression KS 12 Genetische Analyse biologischer Prozesse CS 13 Transposons bei Eukaryonten CS 14 Veränderungen der Chromosomen CS 15 Regulation der Zellzahl - Onkogene CS

3 Mapping and characterization of entire genomes Genetics 09 Based on Chapter 15 (Griffiths; 10th ed.)

4 Summary Genome sequencing Large insert vectors YAC kb BAC kb Phage lambda kb Small insert vectors Plasmids (pbr322, puc18/19) < kb Insert size for sequencing bp Minimal tiling path Paired-end reads Genome sizes Chromosomes and chromosome numbers Exons and introns Synteny Bioinformatics (conserved sequences, exon/intron precictions, cdnas, ESTs, open reading frames)

5 Structure of a eukaryotic gene Elements and sites be recognized by more or less conserved DNA sequence elements, can therefore be predicted by bioinformatics Exon/intron structure particularly important because it allows to predict the sequence of a protein

6 Making gene predictions based on genome sequence

7 How does the availability of genome sequences affect biological analyses?

8 Functional studies - Gene knock outs

9 Functional studies - Gene targeting

10 Functional studies - Gene targeting

11 Functional studies - Insertion mutagenesis

12 Transcriptomics and gene expression profiling Microarrays Heat map

13 Summary Next generation sequencing 1000 genomes project sequencing without cloning and ordering massive parallel sequencing Functional genomics (examples) Gene knock-outs (mammals, yeasts etc.) Gene targeting (mammals) Random insertion mutagenesis (T-DNA, plants) Transcriptomics (Microarrays, gene chips)

14 Gene mutations: their causes and repair mechanisms Genetics 10 Based on Chapter 17 (Griffiths; 10th ed.)

15 Types of gene mutations Spontaneous mutations Induced mutations Quantitating mutagenicity and cancerogenicity Biological repair mechanisms Mutations and cancer

16 Types of gene mutations

17 Structure of a eukaryotic gene

18 Gene mutations - point mutations Transition G:C -> A:T A:T -> G:C C:G -> T:A T:A -> C:G Transversion G:C -> T:A G:C -> C:G T:A -> A:T T:A -> G:C etc.

19 Gene mutations - insertions and deletions (Indels)

20 Indel mutations and replication slippage

21 Mutations can affect splicing

22 Effects of point mutations on transcript and protein

23 Spontaneous mutations

24 Luria-Delbrück s fluctuation test - mutations normally occur spontaneously and randomly

25 Sequencing spontaneous mutations with Next Generation Sequencing

26 Indel mutations and replication slippage

27 Mechanisms of spontaneous mutations

28 Mechanisms of spontaneous mutationsrare tautomeric form can induce mismatch pairings C* -> A T* -> G C -> A* T -> G*

29 Manifestation of a mismatch

30 Spontaneous lesions - depurination

31 G:C -> A:T Spontaneous lesions - deamination

32 Sequencing spontaneous mutations with Next Generation Sequencing

33 Spontaneous lesions - oxidative damage blocks replication G:C -> T:A

34 Trinucleotide repeat mutations in humans: e.g. the FMR-1 gene in Fragile X syndrome

35 Slipped mispairing explains the expansion of trinucleotide repeats

36 Trinucleotide repeat diseases

37 Induced mutations

38 Base analogs (5-BU) 5-Bromouracil (5-BU) 5-BU:A -> C:G

39 Base analogs (2-AP) 2-Aminopurine (2-AP) 2-AP (A):T -> G:C

40 Alkylating agents O C 2 H 5 O S CH 3 O Ethyl methanesulfonate

41 Intercalating agents

42 UV-light induced photoproducts

43 Natural carcinogens - aflatoxins Aspergillus fumigatus

44 Quantitating mutagenicity and carcinogenicity

45 Ames test

46 Ames test - classifying the mechanisms TA100 - sensitive to reversion through base pair substitution TA1535 and TA sensitive to reversions through frame shift mutation

47 Biological repair mechanisms

48 Photolyases repair UV-induced photodimers

49 Homology-dependent repair - base excision repair apurinic/apyrimidinic endonuclease deoxyribophosphodiesterase

50 Homology-dependent repair - GGR and NER

51 Homology-dependent repair - GGR and NER

52 Xeroderma pigmentosum - Mutants in TFIIH

53 Mutations and cancer

54 Mutations can induce cancer

55 The ras oncogene

56 What you need to know and understand for the exam and for your life indels... types of spontaneous mutations... examples for induced mutations... repair mechanisms... Ames test

57 The end