[BioC] delta table interpretation in samr package

Xiang [guest] guest at bioconductor.org
Mon May 27 22:15:15 CEST 2013


Hi, there,
I'm trying to identify differentially expressed genes after treatment using two class paired option of samr function. 

samr.obj<-samr(samData, resp.type="Two class paired", nperms=100)
delta.table<-samr.compute.delta.table(samr.obj, min.foldchange=1.5)

The median FDR rate is 0 for all 50 delta values. The number of called genes remains to be 368 when delta value changes from 0 to 1.09. 

Could anyone let me know if it's OK to use 0 as delta value for samr.compute.siggenes.table? I don't understand why FDR is 0 for delta of 0. Isn't FDR suppose to be 1 if the cutoff value is 0?

thanks a lot

Xiang

 -- output of sessionInfo(): 

           delta # med false pos 90th perc false pos # called median FDR 90th perc FDR         cutlo        cuthi
 [1,] 0.000000000               0           3.9241377      368          0   0.010663418 -2.018916e+00 2.311858e+00
 [2,] 0.001390547               0           3.9241377      368          0   0.010663418 -2.018916e+00 2.311858e+00
 [3,] 0.005562188               0           3.9241377      368          0   0.010663418 -2.018916e+00 2.311858e+00
 [4,] 0.012514923               0           3.9241377      368          0   0.010663418 -2.018916e+00 2.311858e+00
 [5,] 0.022248752               0           3.9241377      368          0   0.010663418 -2.018916e+00 2.311858e+00
 [6,] 0.034763676               0           3.9241377      368          0   0.010663418 -2.018916e+00 2.311858e+00
 [7,] 0.050059693               0           3.9241377      368          0   0.010663418 -2.018916e+00 2.311858e+00
 [8,] 0.068136804               0           3.9241377      368          0   0.010663418 -2.018916e+00 2.311858e+00
 [9,] 0.088995010               0           3.9241377      368          0   0.010663418 -2.018916e+00 2.311858e+00
[10,] 0.112634309               0           3.9241377      368          0   0.010663418 -2.018916e+00 2.311858e+00
[11,] 0.139054703               0           3.9241377      368          0   0.010663418 -2.018916e+00 2.311858e+00
[12,] 0.168256191               0           3.9241377      368          0   0.010663418 -2.018916e+00 2.311858e+00
[13,] 0.200238772               0           3.9241377      368          0   0.010663418 -2.018916e+00 2.311858e+00
[14,] 0.235002448               0           3.9241377      368          0   0.010663418 -2.018916e+00 2.311858e+00
[15,] 0.272547218               0           3.9241377      368          0   0.010663418 -2.018916e+00 2.311858e+00
[16,] 0.312873082               0           3.9241377      368          0   0.010663418 -2.018916e+00 2.311858e+00
[17,] 0.355980039               0           3.9241377      368          0   0.010663418 -2.018916e+00 2.311858e+00
[18,] 0.401868091               0           3.9241377      368          0   0.010663418 -2.018916e+00 2.311858e+00
[19,] 0.450537237               0           3.9241377      368          0   0.010663418 -2.018916e+00 2.311858e+00
[20,] 0.501987477               0           3.9241377      368          0   0.010663418 -2.018916e+00 2.311858e+00
[21,] 0.556218812               0           3.9241377      368          0   0.010663418 -2.018916e+00 2.311858e+00
[22,] 0.613231240               0           3.9241377      368          0   0.010663418 -2.018916e+00 2.311858e+00
[23,] 0.673024762               0           3.9241377      368          0   0.010663418 -2.018916e+00 2.311858e+00
[24,] 0.735599378               0           3.9241377      368          0   0.010663418 -2.018916e+00 2.311858e+00
[25,] 0.800955089               0           3.9241377      368          0   0.010663418 -2.018916e+00 2.311858e+00
[26,] 0.869091893               0           3.9241377      368          0   0.010663418 -2.018916e+00 2.311858e+00
[27,] 0.940009792               0           3.9241377      368          0   0.010663418 -2.018916e+00 2.311858e+00
[28,] 1.013708784               0           3.9241377      368          0   0.010663418 -2.018916e+00 2.311858e+00
[29,] 1.090188871               0           3.9241377      368          0   0.010663418 -2.018916e+00 2.311858e+00
[30,] 1.169450051               0           3.5317239      366          0   0.009649519 -2.018916e+00 2.427889e+00
[31,] 1.251492326               0           3.0957086      365          0   0.008481393 -2.018916e+00 2.648676e+00
[32,] 1.336315695               0           1.3080459      363          0   0.003603432 -2.449141e+00 2.917082e+00
[33,] 1.423920158               0           0.9156321      358          0   0.002557632 -2.449141e+00 3.162520e+00
[34,] 1.514305715               0           0.4796168      354          0   0.001354850 -2.449141e+00 3.542451e+00
[35,] 1.607472366               0           0.4360153      349          0   0.001249327 -2.610891e+00 3.651504e+00
[36,] 1.703420111               0           0.4360153      344          0   0.001267486 -2.888436e+00 3.963871e+00
[37,] 1.802148950               0           0.0000000      340          0   0.000000000 -2.888436e+00 4.458064e+00
[38,] 1.903658883               0           0.0000000      335          0   0.000000000 -3.045751e+00 4.458064e+00
[39,] 2.007949910               0           0.0000000      327          0   0.000000000 -3.180299e+00 4.516839e+00
[40,] 2.115022031               0           0.0000000      317          0   0.000000000 -3.351132e+00 4.819126e+00
[41,] 2.224875247               0           0.0000000      306          0   0.000000000 -3.547589e+00 4.873843e+00
[42,] 2.337509556               0           0.0000000      288          0   0.000000000 -3.754290e+00 5.592262e+00
[43,] 2.452924959               0           0.0000000      261          0   0.000000000 -3.953790e+00 5.592262e+00
[44,] 2.571121457               0           0.0000000      222          0   0.000000000 -4.185488e+00 5.592262e+00
[45,] 2.692099048               0           0.0000000      145          0   0.000000000 -4.499563e+00 5.592262e+00
[46,] 2.815857734               0           0.0000000       64          0   0.000000000 -4.875999e+00 1.000000e+10
[47,] 2.942397514               0           0.0000000       31          0   0.000000000 -5.176429e+00 1.000000e+10
[48,] 3.071718387               0           0.0000000       21          0   0.000000000 -5.400854e+00 1.000000e+10
[49,] 3.203820355               0           0.0000000        2          0   0.000000000 -6.214298e+00 1.000000e+10
[50,] 3.338703417               0           0.0000000        0        NaN           NaN -1.000000e+10 1.000000e+10


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