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1. Copy Number Alterations with Massively Parallel Sequencing Presented By Robert Shields
Case Western Reserve University
June 3rd, 2009
2. Motivation Identify differences in copy number variation between normal and cancer cells
3. Copy Number Ratio Partition the genome into windows of length L
L (10kb 100kb)
Look at copy number ratios in each window
4. Statistical Power of Fixed Window Need ~15 million aligned reads to detect one gain
Need ~6 million aligned reads to detect one loss
5. SegSeq Step One Step One: Identify Possible Break Points
D : Difference in ratios from two adjacent windows
W : number of consecutive reads from normal sample
6. SegSeq Step One
7. SegSeq Step Two Calculate P-values of potential break points based on number of tumor reads
8. SegSeq Step Two If the Pvalue < Pinit we keep it as a candidate break point
9. SegSeq Step Three If the Pvalue > Pmerge we merge the segments
Calculate P values on newly formed segments
10. Comparing the Steps
11. Sensitivity to Gain and Loss
12. Results
13. Results