Breakdancer Max Kahan Error:0
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3
Entering edit mode
10.7 years ago
Jack ▴ 80

I'm using breakdancer-max 1.4.4-unstable-7-6213d5a on exome sequencing data from tumor-normal pairs (all from Illumina HiSeq 2500, 200x coverage, whole exome using NimbleGen Exome v3.0). BAM files are ~40Gb in size, all quality-trimmed using fastqc, aligned using BWA-sampe, processed using GATK pipeline (remove duplicates, do indel realignment, relirecalibrate base quality score).

I first generate the config file using

bam2cfg.pl -g -h tumor.bam normal.bam >  t.cfg

The output is

readgroup:CGATGT.L002    platform:ILLUMINA    map:t.bam    readlen:101.00    lib:310.T1.CGATGT    num:9984    lower:0.00    upper:760.11    mean:245.43    std:101.07    SWnormality:-59.31    flag:0(13.62%)18(85.59%)2(0.13%)32(0.43%)4(0.23%)10771    exe:samtools view
    readgroup:CGATGT.L001    platform:ILLUMINA    map:t.bam    readlen:101.00    lib:310.T1.CGATGT    num:9984    lower:0.00    upper:760.11    mean:245.43    std:101.07    SWnormality:-59.31    flag:0(11.15%)18(88.06%)2(0.12%)32(0.53%)4(0.13%)8(0.02%)12148    exe:samtools view
    readgroup:ATCACG.L002    platform:ILLUMINA    map:n.bam    readlen:101.00    lib:310.N.ATCACG    num:9994    lower:0.00    upper:737.03    mean:241.92    std:99.54    SWnormality:-57.95    flag:0(14.29%)18(84.85%)2(0.11%)32(0.47%)4(0.27%)9586    exe:samtools view
    readgroup:ATCACG.L001    platform:ILLUMINA    map:n.bam    readlen:101.00    lib:310.N.ATCACG    num:9994    lower:0.00    upper:737.03    mean:241.92    std:99.54    SWnormality:-57.95    flag:0(12.77%)18(86.36%)2(0.11%)32(0.55%)4(0.21%)10618    exe:samtools view

I run breakdancer as shown below

breakdancer-max -q 10 -d t t.cfg > t.ctx

The run takes about 90 min, and it terminates with a "Max Kahan error:0." However, it also produces a 16Mb .ctx file. The file contains calls from all chromosomes, so it seems like breakdancer-max ran fine, except the error message. First couple lines from the output is below.

#Software: 1.4.4-unstable-7-6213d5a (commit 6213d5a)
#Command: breakdancer-max -q 10 -d t t.cfg 
#Library Statistics:
#n.bam    mean:241.92    std:99.54    uppercutoff:737.03    lowercutoff:0    readlen:101    library:310.N.ATCACG    reflen:3052047611    seqcov:6.83207    phycov:8.18225    1:14714    2:393238    4:426044    8:16096    32:569558
#t.bam    mean:245.43    std:101.07    uppercutoff:760.11    lowercutoff:0    readlen:101    library:310.T1.CGATGT    reflen:3052047611    seqcov:6.77381    phycov:8.23018    1:15354    2:549576    4:367739    8:16740    32:635131
#Chr1    Pos1    Orientation1    Chr2    Pos2    Orientation2    Type    Size    Score    num_Reads    num_Reads_lib    310.bam    310t.bam
chrM    4    6+17-    chrM    16564    17+3-    ITX    16001    99    14    n.bam|8:t.bam|6    129.24    111.03
chrM    509    100+26-    chrM    743    100+26-    ITX    -144    99    12    n.bam|8:t.bam|4    NA    NA
chrM    839    100+26-    chrM    1201    2+4-    DEL    535    46    2    t.bam|2    124.40    100.40
chrM    828    3+11-    chrM    3198    151+249-    ITX    -144    99    58    .bam|32:t.bam|26    6.05    5.05
chrM    3102    151+249-    chrM    3160    1+11-    DEL    584    98    8    .bam|4:t.bam|4    47.92    45.76

I saw older unresolved posts on Biostar about the same issue. (Error Running Breakdancer-Max: Max Kahan Error: 0) I was wondering if anyone came up with a solution since then.

Thanks.

breakdancer error • 3.7k views
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5
Entering edit mode
10.7 years ago
ernfrid ▴ 400

That is a status message. It is shown every time that BreakDancer runs and does not indicate that BreakDancer had a problem while it was running. Your results are valid.

We will consider changing the wording of that message or removing it all together.

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2
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...that's quite possibly the worst status message ever... Nice tool, though. :)

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1
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Agreed lol. I added that a long time ago when I was worried about numerical precision in the scoring code, and never got around to taking it out... until now. It's gone in master on github :)

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2
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I got intrigued, who is Max Kahan, whose Error of Zero should be taken as a good sign.

Then I realized! It must be the maximal Kahan summation error that we're happy to see at being zero.

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1
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That's hilarious! I've been thinking it was an inside joke, a reference to a TV show I've never seen or something similar. Google gave me this, which kind of puzzled me... http://www.crainsnewyork.com/article/20131117/FINANCE/311179997/max-kahan-sets-the-gold-standard#

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