©M J Larkin Biology & Biochemistry. The Queen’s University of Belfast. Level 2 Genetic Systems. M J Larkin ©M J Larkin Biology & Biochemistry. The Queen’s University of Belfast.

Dr Mike Larkin - Communication MBC Room 113 –xt 2288 (Belfast Diverted to the DKB) DKB Questor Centre Room 318a – 3rd Floor Microbiology Laboratory – xt (90977) 4390 or (90977)4388 lab’ or (9033) 5577 office Pigeon hole in Biology & Biochemistry office ALWAYS LEAVE MESSAGE and HOW TO CONTACT YOU!

©M J Larkin Biology & Biochemistry. The Queen’s University of Belfast. Dr Mike Larkin - Communication continued WWW PAGES ml

©M J Larkin Biology & Biochemistry. The Queen’s University of Belfast. Course Theme: reminder Half of the course dedicated to Microbial Genetics. Primarily Prokaryote Genetics. An introduction to bacteria and their genetic systems. ° Transfer of genes BETWEEN cells in bacteria ° Bacteriophages and plasmids (JQ) ° The fate of DNA WITHIN bacterial cells ° Mutation, recombination, repair, transposition (ML) ° Introduction to genomics and genome mapping (ML)

©M J Larkin Biology & Biochemistry. The Queen’s University of Belfast. Reading There are many texts with clear explanations e.g. –Maloy S R et al (2001) Microbial Genetics. 4th Edition Jones and Bartlett. ISBN: QH434/MALO - A comprehensive text and good introduction – 2004 edition due out –Winter P et al (1998)Instant Notes in Genetics. Oxford:BIOS Scientific. ISBN QH440.2/WINT - Not a great coverage of bacterial genetics but useful nevertheless for recombination A good primer text for this part of the course is Dale J.W. (2004) Molecular Genetics of Bacteria. 5th Edition Wiley ISBN: X QH434.D35.  DIRECTED READING will be indicated.

©M J Larkin Biology & Biochemistry. The Queen’s University of Belfast. Lectures Introduction. The basis of diversity –Mutation, homologous recombination and repair (3 lectures) Non-homologous recombination –Mechanisms of transposition (2 lectures) Genomics and genome mapping –Pre-genomic techniques –Prokaryote genome sequencing (2 lectures) Revision tutorial

©M J Larkin Biology & Biochemistry. The Queen’s University of Belfast. Practicals : Aims 1. Phage restriction –Observe phage restriction and consider the implications of this phenomenon in nature. –Acquire the skills needed to cultivate and titre phage in practice 2. Phage co-transduction –Demonstrate the close linkage of two bacterial genes by transductional mapping –Observe the connection between RecA function and DNA repair 3. Conjugation and transposition –Demonstrate plasmid conjugation –Demonstrate Insertion Sequence transposition/cointegration

©M J Larkin Biology & Biochemistry. The Queen’s University of Belfast. Introduction: the basis of diversity. A. What you should know B. Terminology C. Breeding systems D. Types of mutation E. Reversion and suppression F. Mechanisms of mutation G. DNA damage repair H. Homologous recombination I. Homologous recombination and repair LECTURE 1 2 3

©M J Larkin Biology & Biochemistry. The Queen’s University of Belfast. Introduction A. What you should know. – From Level 1 Courses – The basis of the genetic code – DNA replication – The structure of the bacterial chromosome  Maloy and Dale cover introductory material well.  DNA structure and basis of code well covered in Winter A1

©M J Larkin Biology & Biochemistry. The Queen’s University of Belfast. Chromosomal replication is bidirectional Cairns (1963) and Rodriguez (1973) Autoradiography - 3 H labelled DNA oriC

©M J Larkin Biology & Biochemistry. The Queen’s University of Belfast. The structure of the bacterial Chromosome Lysed E.coli cell (lysozyme) Growing cells showing Geimsa stained condensed chromosome

©M J Larkin Biology & Biochemistry. The Queen’s University of Belfast. Introduction cont……. B. Terminology. See Practical schedule. –The biggest source of confusion in practice –Strains given numbers: e.g. AB1157 –Mutant genotype written as: e.g. arg lac Z –Phenotype written as: e.g. Arg or Lac Z –( C1857) or (P1Cm ) Lysogenic or cells “carrying” these phage –(pOXKm) cells “carrying” this plasmid – srlC::Tn10 indicates presence of transposon (or IS) in this gene –Mutant or Mutation –Auxotrophic or Prototrophic –Mutant selection or mutant screening  Dale Ch 2, Glossary and appendices are very useful.

©M J Larkin Biology & Biochemistry. The Queen’s University of Belfast. Introduction cont……. C. Breeding Systems. –Eukaryotes possess a SEXUAL CYCLE  DIPLOID 2n HAPLOID 1n

©M J Larkin Biology & Biochemistry. The Queen’s University of Belfast. C. Breeding Systems. cont……. Variation arises from from: – Mutation, recombination and random assortment E.g : Two Chromosomes randomly assorted. A a B b A B a B a b A b DIPLOID 2n HAPLOID 1n 4 x possibilities at Meiosis 3 Chromosomes possibilities n chromosomes n possibilities

©M J Larkin Biology & Biochemistry. The Queen’s University of Belfast. C. Breeding Systems. cont……. Humans have 2 23 POSSIBILITIES ! Assuming 2 -3 crossovers per chromosome (i.e. about 60 in total) = (2 23 ) 60 variants possible in Meiosis ! Mutation rate may be only 1 in 20,000 to 200,000 per chromosome. Mutation adds variants at a low rate. If too high then a high GENETIC LOAD. Therefore: Meiosis increases overall variation at a high frequency without a detrimental “Genetic Load”.

©M J Larkin Biology & Biochemistry. The Queen’s University of Belfast. C. Breeding Systems. cont……. What about Prokaryotes ? –No MEIOSIS possible –Asexual reproduction –Single Chromosome with plasmids –Genetic recombination NOT associated with reproduction –Mutation rate at single loci about 1 in 10 8 to per cell per generation How is variability generated then ? –At the gene transfer population GENE POOL level –Complex mutation/recombination systems within cells

©M J Larkin Biology & Biochemistry. The Queen’s University of Belfast. The basis of diversity in bacteria °DNA Replication °Mutation °Repair °Recombination °Homologous °Non-homologous °Rearrangements/transpositions °Deletions DNA Transformation Phage Transduction Plasmid Conjugation