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Mo17 shotgun project Goal: sequence Mo17 gene space with inexpensive new technologies Datasets in progress: Four-phases of 454-FLX sequencing to max of.

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Presentation on theme: "Mo17 shotgun project Goal: sequence Mo17 gene space with inexpensive new technologies Datasets in progress: Four-phases of 454-FLX sequencing to max of."— Presentation transcript:

1 Mo17 shotgun project Goal: sequence Mo17 gene space with inexpensive new technologies Datasets in progress: Four-phases of 454-FLX sequencing to max of ~12X Include ~3kb paired-end sequencing (for short-range structural variation) Ultra-short-read Solexa or ABI-SOLID (for polishing) Preparation of methyl-spanning linkers to augment IBM map integration, detect rearrangements (Sanger end-sequence) (Ideally would add Mo17 BAC-ends from DuPont, if available)

2 Shotgun Independent of tiling path -Can detect non-repetitive gene space even within otherwise complex regions that may not be in tiling path Disadvantages of short-reads -Cant expect to recover repetitive sequences

3 Four Phases of Sequencing Complete in 2007 Sequencing contract established with 454/Roche. Four Phases, including collaborative runs at no cost in P2-4. Phase I underway (30 FLX runs.) Library QC and initial assessment of data quality (30 FLX runs). 10 FLX runs totaling 1 Gb (~0.4X) 20 FLX pair runs spanning 12 Gb (~5X span in 3kb inserts) Assess quality, coverage, contamination, chimerism, accuracy Phase II. (80 runs plus 30 runs from Roche, total 110 runs). Rough draft stage. 40 FLX-pair runs spanning 36 Gb (total 48 Gb~10X span) 70 FLX runs for 7 Gb (total 8Gb ~3.5X sequence) Assess rough draft assembly (3 methods), compare B73, sorghum

4 Phases III and IV Phase III (50 runs + 20 contributed) –20 FLX-pair runs (total spanning cover ~20X) –50 FLX runs (total 13 Gb sequence ~5.5X) –Draft assembly. Rough annnotation. Assessment of structural variation based on 20X clone cover. Assessment complete by end of 2007. Phase IV (60 runs + 30 contributed) –90 FLX runs (to reach total 22 Gb ~10X) –Data collection complete by end of 2007. –Early 08. Final assembly. Integration with MSSL ends and IBM map. Proceed to annotation and full analysis. Note: Later phases may use next FLX release with longer read lengths. To be conservative, sequence from FLX-pair reads not included in sequence coverage estimates. Total sequencing cost for Phase I-IV: $1.6M

5 454-FLX reads are typically either mostly masked, or mostly clean 0 0.5 1.0 Percent masked by over-repd 16mers ~29% of reads have < quarter of positions masked ~58% of reads have > 2/3 of positions masked

6 Mo17 454 unique full length alignments vs. B73 MAGIs show high quality of unique alignments Residual repeats in MAGIs with multiple hits in 454 data Unique full alignments

7 SNPs and indels of 454 reads relative to MAGIs consistent with few % variation of Mo17/B73 (combines variation with sequencing errors) SNPs or indels per base Frequency of reads

8 Multiple assembly alternate plans Divide and conquer –Reduce ~100 million reads to ~50K unique gene spaces of ~thousands of reads each (~10kb) by clustering based on various comparisons Plan A: De novo clustering of masked reads Plan B: map to B73, assemble (de novo for remainder) Plan C: sorghum-assisted –Use various assemblers to lay-out and produce consensus for each cluster (454 assembly team engaged) –Polish sequence with Solexa or SOLID for accuracy –Link with MSSL pairs, integrate with map

9 Backup analyses vs. B73 reference SNP/variation detection by alignment to B73 sequence -454/Solexa/Solid (various successful models in other species at JGI, elsewhere) Structural variation detection via paired-end placements -Needs to be tolerant of chimerism rate -Model of successful human structural analysis done with 454 (unpublished)

10 Timeline Phase I in progress, complete by end of month. Analysis to OK phase II ~10 days. Phase II: October Phase III: November Phase IV: December 454 sequencing complete by end of year

11 ~58% of each BAC is masked by over-represented 16-mers

12 Outreach Dick McCombie

13 Types of Outreach Public presentations Collaborations CSHL DNA Learning Center

14 Public Presentations

15 Collaborations –The Maize Genetics and Genomics Database. --Letter for Carolyn Lawrence-MaizeGDB –MaizeGDB-web site text, links to data –Gramene –EBI Ensembl –Affymetrix Maize Pilot Expression Array Project –Optical map –TWINSCAN –Vmatch –Full-Length cDNA Project

16 CSHL DNA Learning Center http://www.dnalc.org/maize/maize.html


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