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16 th April 2007 Christine Nicholson, Mapping Core Group Wellcome Trust Sanger Institute Tomato Chromosome 4 Mapping & Use of FPC Copyright Wellcome Trust Medical Photographic Library
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Tomato Genome Sequencing Strategy BAC by BAC sequencing Seed BACs selected for sequencing using mapped markers BAC selection from the physical map: constructed using restriction fingerprint digests & mapped marker information → orders & orientates contigs
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Tomato Genome Sequencing Strategy Shotgun subclone & sequence Annotation : MIPs Imperial College London Overlapping BACs anchored by mapped markers Minimal tiling path “Finishing” Gap closure Problem solving Contiguous < 1 error in 10,000 …….. TAGCTGTGTACGATGATC ………. ~15 contigs per clone EMBL GenBank DDBJ Markers EMBL GenBank DDBJ Computer assembly – paired plasmid reads
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WTSI Sequencing Pipeline - Tomato FinishingQC Mapping Sub- cloning Production Shotgun sequencing AB 3730 Auto Pre- Finishing
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BAC Library & Map Resources LibraryNo. of clones Average Insert Genome equivalents Coverage in fingerprints End Sequenced ? LE_HBa129,024117 kb15 X10 XYes SL_MboI52,992135 kb7 X-Yes SL_EcoI72,26495-100 kb7 X-Yes FPC Database Agarose gel fingerprints ~ 10 X fingerprint coverage BAC End Sequences Available for all three libraries
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Fingerprinting – SL_MboI Library 1. Increase map coverage 2. Fingerprint data from > 1 library 3. Make clones visible in FPC - Assess potential deletions? 4. Additional resource for community Why fingerprint additional BACs ? How the fingerprinting was conducted……….
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Agarose Gel Fingerprinting Digitised on: Amersham Typhoon 8600 Scanner Why agarose fingerprinting? Same protocol as AGI Same marker Integrate datasets
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Processing Fingerprint Data Digitised agarose gel From the SL_MboI library: > 43,000 fingerprints generated Marker every 5 th well across gel
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Image Gel Images processed using Image: (http://www.sanger.ac.uk/Software/Image/) Marker Locked (Standard - from AGI) Band called Lane tracked
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WTSI Prefixes – Clone Names Library PrefixWTSI Internal Prefix LE_HBabTH SL_MboIbTM SL_EcoRIbTE EMBL/GenBank accessions released with International Prefix
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Confirmation of Fingerprint Placement Re-built FPC with fingerprints from both libraries Fingerprint placements verified and confirmed by BAC End Sequence
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Accessing SL_MboI Fingerprint Data Fingerprint data can also be accessed from SGN ftp://ftp.sanger.ac.uk/pub/tomato/map/ Assembled database available at: (sizes, bands, gels files available) General FPC info: http://www.sanger.ac.uk/Software/fpc/
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http://www.sgn.cornell.edu/about/tomato_sequencing.pl
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BAC Library & Map Resources – April ’07 LibraryNo. of clones Average Insert Genome equivalents Coverage in fingerprints End Sequenced ? LE_HBa129,024117 kb15 X10 XYes SL_MboI52,992135 kb7 X6 XYes SL_EcoI72,26495-100 kb7 X-Yes Increased map coverage – fingerprints Fingerprint data – multiple libraries Visible – fingerprint assessed for sequence BAC selection Public
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Anchoring Contigs to Chromosome 4 Tomato EXPEN-2000 map FPC Contig Analysis In silico assessment contigs with chromosome 4 markers Contigs merged with supporting evidence → longer minimal tile paths Use of BES and fingerprint data for BAC selection Overgo analysis at Cornell Some examples of chromosome 4 contigs……
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Assessing & Editing Chromosome 4 Contigs Sequence BACs highlighted Chr 4 marker
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Marker has several overgo hits in contig
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Assessing & Editing Chromosome 4 Contigs Chr 4 marker Tilepath selection from anchored BAC
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A further Chromosome 4 Contig
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Marker has ONE hit in contig bTH53M2 FISHed to long arm, chromosome 4 → same region as marker All FPC contigs with chromosome 4 markers examined & assessed individually
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Selection of Minimal Tiling Paths – Using BES Tile Path selected from initial chromosome 4 confirmed clone Design probes from BES Confirm overlaps by colony PCR Selecting minimal tiling paths across chromosome 4 contigs
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Additional Uses of Fingerprints FinishingQC Mapping Sub- cloning Production Shotgun sequencing Auto Pre- Finishing Fingerprint confirmation Digest confirmed with original FP
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Digest Check Prior to Sequencing Confirm HindIII digested DNA against original map fingerprint
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Additional Uses of Fingerprints FinishingQC Mapping Sub- cloning Production Shotgun sequencing Auto Pre- Finishing Fingerprint confirmation Digest confirmed with original FP Digest information utilised
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BAC Registration at SGN
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Identifying Further Chromosome Coverage Screen unanchored markers Walk from contig ends by hybridization Grid libraries to generate filters CHROMOSOME VERIFICATION : Confirmation of Overlaps by PCR using BES Genetic Mapping FISH
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FISH Analysis 36C23 20F17 114C15 198L24 & 119A16 308B7 6E18 78E4 132O11 53M2 106F7 36C23 114C15 308B7 6E18 198L24 & 119A16 20F17 78E4 132O11 53M2 106F7 Tomato-EXPEN 2000 FISH OBSERVATIONS: Euchromatin confirmation Slight marker order variation around centromere/heterochromatin Islands of heterochromatin within euchromatin Gene space requires further definition
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Potential Use of Fosmid End Sequences Fosmids Smaller than BACs Sheared Known insert sizes Contig Extension & Gap Closure Assembly Confirmation
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Acknowledgements Wellcome Trust Sanger Institute: Jane Rogers Sean Humphray Paul Hunt Mark Maddison Richard Clark Kate Fraser Rebecca Hannah Subcloning Shotgun Sequencing Finishing Imperial College London: Gerard Bishop Daniel Buchan James Abbott Sarah Butcher University of Nottingham: Graham Seymour Scottish Crop Research Institute: Glenn Bryan Cornell University: Lukas Mueller Jim Giovannoni Steve Tanksley Yimin Xu Colorado State University: Stephen Stack Suzanne Royer Song-Bin Chang Arizona Genomics Institute: Rod Wing Seunghee Lee MIPS/IBI Institute for Bioinformatics: Klaus Mayer Remy Bruggmann FUNDING Mapping Core Group
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