[BioC] [limma] Strange results in contrasts with dye-swap

mjonczyk at biol.uw.edu.pl mjonczyk at biol.uw.edu.pl
Sat Aug 20 11:06:11 CEST 2011


Dear Gordon & List Members,

I've made few hybridizations which I'd like to incorporate to the design
described in this thread (It was reference design, two temperature treatments
with seven samples (time points) in both, all compared directly to "time 0" sample).

Treatments I'd like to merge with that experiment are direct comparison of:

c2 vs k2
c6 vs k6
c8 vs k8

As main experiment this comparisons were repeated four times with dye-swap (two
labellings in both directions), using the same biological material as in
corresponding replications in the main experiment.

Here is my new target frame:

FileName	Cy3	Cy5	powt
_024_1_vs_7ex.gpr	k0	k2	1
_228_k0_vs_16ex.gpr	k0	c12	1
_229_k0_vs_8ex.gpr	k0	c4	1
_230_k0_vs_15ex.gpr	k0	k10	1
_235_k0_vs_19ex.gpr	k0	k14	1
_237_k0_vs_14ex.gpr	k0	c10	1
_238_k0_vs_10ex.gpr	k0	c6	1
_239_k0_vs_12ex.gpr	k0	c8	1
_240_k0_vs_13ex.gpr	k0	k8	1
_248_k0_vs_17ex.gpr	k0	k12	1
_249_k0_vs_9ex.gpr	k0	k4	1
_253_k0_vs_11ex.gpr	k0	k6	1
_254_k0_vs_6ex.gpr	k0	c2	1
_256_k0_vs_18ex.gpr	k0	c14	1
_189_K8_vs_K0ex.gpr	k8	k0	2
_190_K4_vs_K0ex.gpr	k4	k0	2
_191_K6_vs_K0ex.gpr	k6	k0	2
_192_C8_vs_K0ex.gpr	c8	k0	2
_193_C10_vs_K0ex.gpr	c10	k0	2
_194_C2_vs_K0ex.gpr	c2	k0	2
_198_C14_vs_K0ex.gpr	c14	k0	2
_200_K12_vs_K0ex.gpr	k12	k0	2
_202_K10_vs_K0ex.gpr	k10	k0	2
_206_C6_vs_K0ex.gpr	c6	k0	2
_207_C12_vs_K0ex.gpr	c12	k0	2
_208_K2_vs_K0ex.gpr	k2	k0	2
_209_K14_vs_K0ex.gpr	k14	k0	2
_210_C4_vs_K0ex.gpr	c4	k0	2
_201_k0_vs_C2ex.gpr	k0	c2	3
_203_k0_vs_K6ex.gpr	k0	k6	3
_205_k0_vs_C12ex.gpr	k0	c12	3
_217_k0_vs_K14ex.gpr	k0	k14	3
_219_k0_vs_C4ex.gpr	k0	c4	3
_231_k0_vs_C10ex.gpr	k0	c10	3
_232_k0_vs_K8ex.gpr	k0	k8	3
_233_k0_vs_C8ex.gpr	k0	c8	3
_234_k0_vs_C14ex.gpr	k0	c14	3
_235_k0_vs_C6ex.gpr	k0	c6	3
_236_k0_vs_K10ex.gpr	k0	k10	3
_237_k0_vs_K2ex.gpr	k0	k2	3
_238_k0_vs_K4ex.gpr	k0	k4	3
_239_k0_vs_K12ex.gpr	k0	k12	3
_004_8_vs_1ex.gpr	c8	k0	4
_005_10_vs_1ex.gpr	c10	k0	4
_006_2_vs_1ex.gpr	c2	k0	4
_007_15_vs_1ex.gpr	k14	k0	4
_008_4_vs_1ex.gpr	c4	k0	4
_010_3_vs_1ex.gpr	k2	k0	4
_011_9_vs_1ex.gpr	k8	k0	4
_012_14_vs_1ex.gpr	c14	k0	4
_014_12_vs_1ex.gpr	c12	k0	4
_026_13_vs_1ex.gpr	k12	k0	4
_036_11_vs_1ex.gpr	k10	k0	4
_037_6_vs_1ex.gpr	c6	k0	4
_043_7_vs_1ex.gpr	k6	k0	4
_044_5_vs_1ex.gpr	k4	k0	4
127	k2	c2	1
049	c2	k2	2
133	c2	k2	4
128	k2	c2	3
047	k6	c6	1
050	c6	k6	2
046	c6	k6	4
048	k6	c6	3
130	k8	c8	1
134	c8	k8	2
132	c8	k8	4
045	k8	c8	3

So design matrix will be
> xdesign=modelMatrix(xtrg,ref="k0")
> xdesign
      c10 c12 c14 c2 c4 c6 c8 k10 k12 k14 k2 k4 k6 k8
 [1,]   0   0   0  0  0  0  0   0   0   0  1  0  0  0
 [2,]   0   1   0  0  0  0  0   0   0   0  0  0  0  0
 [3,]   0   0   0  0  1  0  0   0   0   0  0  0  0  0
 [4,]   0   0   0  0  0  0  0   1   0   0  0  0  0  0
 [5,]   0   0   0  0  0  0  0   0   0   1  0  0  0  0
 [6,]   1   0   0  0  0  0  0   0   0   0  0  0  0  0
 [7,]   0   0   0  0  0  1  0   0   0   0  0  0  0  0
 [8,]   0   0   0  0  0  0  1   0   0   0  0  0  0  0
 [9,]   0   0   0  0  0  0  0   0   0   0  0  0  0  1
[10,]   0   0   0  0  0  0  0   0   1   0  0  0  0  0
[11,]   0   0   0  0  0  0  0   0   0   0  0  1  0  0
[12,]   0   0   0  0  0  0  0   0   0   0  0  0  1  0
[13,]   0   0   0  1  0  0  0   0   0   0  0  0  0  0
[14,]   0   0   1  0  0  0  0   0   0   0  0  0  0  0
[15,]   0   0   0  0  0  0  0   0   0   0  0  0  0 -1
[16,]   0   0   0  0  0  0  0   0   0   0  0 -1  0  0
[17,]   0   0   0  0  0  0  0   0   0   0  0  0 -1  0
[18,]   0   0   0  0  0  0 -1   0   0   0  0  0  0  0
[19,]  -1   0   0  0  0  0  0   0   0   0  0  0  0  0
[20,]   0   0   0 -1  0  0  0   0   0   0  0  0  0  0
[21,]   0   0  -1  0  0  0  0   0   0   0  0  0  0  0
[22,]   0   0   0  0  0  0  0   0  -1   0  0  0  0  0
[23,]   0   0   0  0  0  0  0  -1   0   0  0  0  0  0
[24,]   0   0   0  0  0 -1  0   0   0   0  0  0  0  0
[25,]   0  -1   0  0  0  0  0   0   0   0  0  0  0  0
[26,]   0   0   0  0  0  0  0   0   0   0 -1  0  0  0
[27,]   0   0   0  0  0  0  0   0   0  -1  0  0  0  0
[28,]   0   0   0  0 -1  0  0   0   0   0  0  0  0  0
[29,]   0   0   0  1  0  0  0   0   0   0  0  0  0  0
[30,]   0   0   0  0  0  0  0   0   0   0  0  0  1  0
[31,]   0   1   0  0  0  0  0   0   0   0  0  0  0  0
[32,]   0   0   0  0  0  0  0   0   0   1  0  0  0  0
[33,]   0   0   0  0  1  0  0   0   0   0  0  0  0  0
[34,]   1   0   0  0  0  0  0   0   0   0  0  0  0  0
[35,]   0   0   0  0  0  0  0   0   0   0  0  0  0  1
[36,]   0   0   0  0  0  0  1   0   0   0  0  0  0  0
[37,]   0   0   1  0  0  0  0   0   0   0  0  0  0  0
[38,]   0   0   0  0  0  1  0   0   0   0  0  0  0  0
[39,]   0   0   0  0  0  0  0   1   0   0  0  0  0  0
[40,]   0   0   0  0  0  0  0   0   0   0  1  0  0  0
[41,]   0   0   0  0  0  0  0   0   0   0  0  1  0  0
[42,]   0   0   0  0  0  0  0   0   1   0  0  0  0  0
[43,]   0   0   0  0  0  0 -1   0   0   0  0  0  0  0
[44,]  -1   0   0  0  0  0  0   0   0   0  0  0  0  0
[45,]   0   0   0 -1  0  0  0   0   0   0  0  0  0  0
[46,]   0   0   0  0  0  0  0   0   0  -1  0  0  0  0
[47,]   0   0   0  0 -1  0  0   0   0   0  0  0  0  0
[48,]   0   0   0  0  0  0  0   0   0   0 -1  0  0  0
[49,]   0   0   0  0  0  0  0   0   0   0  0  0  0 -1
[50,]   0   0  -1  0  0  0  0   0   0   0  0  0  0  0
[51,]   0  -1   0  0  0  0  0   0   0   0  0  0  0  0
[52,]   0   0   0  0  0  0  0   0  -1   0  0  0  0  0
[53,]   0   0   0  0  0  0  0  -1   0   0  0  0  0  0
[54,]   0   0   0  0  0 -1  0   0   0   0  0  0  0  0
[55,]   0   0   0  0  0  0  0   0   0   0  0  0 -1  0
[56,]   0   0   0  0  0  0  0   0   0   0  0 -1  0  0
[57,]   0   0   0  1  0  0  0   0   0   0 -1  0  0  0
[58,]   0   0   0 -1  0  0  0   0   0   0  1  0  0  0
[59,]   0   0   0 -1  0  0  0   0   0   0  1  0  0  0
[60,]   0   0   0  1  0  0  0   0   0   0 -1  0  0  0
[61,]   0   0   0  0  0  1  0   0   0   0  0  0 -1  0
[62,]   0   0   0  0  0 -1  0   0   0   0  0  0  1  0
[63,]   0   0   0  0  0 -1  0   0   0   0  0  0  1  0
[64,]   0   0   0  0  0  1  0   0   0   0  0  0 -1  0
[65,]   0   0   0  0  0  0  1   0   0   0  0  0  0 -1
[66,]   0   0   0  0  0  0 -1   0   0   0  0  0  0  1
[67,]   0   0   0  0  0  0 -1   0   0   0  0  0  0  1
[68,]   0   0   0  0  0  0  1   0   0   0  0  0  0 -1

*Is* it correct? I.e. is it make correct use of direct (cx vs kx) comparisons?

*Can* I use the same code as previously

> xdesign_dye=cbind(DyeEffect=1,xdesign)
> fit.userguide.dye=lmFit(img_lA_ncav,xdesign_dye)
>
contrast.matrix.d=makeContrasts(p2="c2-k2",p4="c4-k4",p6="c6-k6",p8="c8-k8",p10="c10-k10",p12="c12-k12",p14="c14-k14",levels=xdesign_dye)
> fit2.ug.d=contrasts.fit(fit.userguide.dye,contrast.matrix.d)
> fit2.ug.d=eBayes(fit2.ug.d)
> test.ug.d=decideTests(fit2.ug.d,method="global",adjust.method="BH",p.value=0.05)

Thanks in advance,
Best Regards,

Maciej Jończyk, MSc
Department of Plant Molecular Ecophysiology
Institute of Plant Experimental Biology
Faculty of Biology, University of Warsaw
02-096 Warszawa, Miecznikowa 1

> On Fri, 5 Aug 2011, mjonczyk at biol.uw.edu.pl wrote:
> 
> > Dear Gordon,
> >
> > thank you for clarifying this issue.
> >
> >
> >>> Results:
> >>>
> >>> TEST WITHOUT DYE EFFECT
> >>>> summary(test.ug)
> >>>   c2 - k2 c4 - k4 c6 - k6 c8 - k8 c10 - k10 c12 - k12 c14 - k14
> >>> -1     115      96     377     141       263       175       265
> >>> 0    43082   43048   42326   42973     42694     42842     42752
> >>> 1      196     249     690     279       436       376       376
> >>>
> >>>
> >>> TEST WITH DYE EFFECT
> >>>> summary(test.ug.d)
> >>>      p2    p4    p6    p8   p10   p12   p14
> >>> -1   246   217   686   317   530   316   526
> >>> 0  42797 42755 41594 42530 42103 42446 42239
> >>> 1    350   421  1113   546   760   631   628
> >>>
> >>> TEST WITH DYE EFFECT AND CONTRAST FOR DYE EFFECT
> >>>> summary(test.ug.d2)
> >>>   DyeEffect    p2    p4    p6    p8   p10   p12   p14
> >>> -1      6660   452   402  1103   593   858   539   883
> >>> 0      30803 42353 42261 40659 41853 41359 41888 41564
> >>> 1       5930   588   730  1631   947  1176   966   946
> >>>
> >
> >> The lesson here is that you should not include DyeEffect in decideTests()
> >> with your other contrasts.  When using method="global", you should only
> >> include contrasts that are closely comparable to one another, and about
> >> which you will be making conclusions as a group.
> >>
> >>> *OTHER QUESTIONS*
> >>> 1. Is second model (WITH DYE EFFECT) correct?
> >>
> >> Fine.
> >>
> > Ok, so I use this model and "global" method.
> >>
> >>
> >>> 4. Should I include biol-replication effect in analysis (as block)?
> >>
> >> If the biol replicates seem to vary randomly, and are only slightly
> >> different, then I would suggest that you enter them as a random effect
> >> using block instead.  If there are large differences between the biol
> >> reps, in particular if one rep is different to the others, then including
> >> them in the design matrix as you have done is safer and probably better.
> >
> > The second scenario is true in this experiment, from PCA I know that differences
> > between replications isn't negligible.
> > So replication effect is already included, just because in target frame (and
> > consequently design matrix) each combination of samples on array is repeated
> > four times?
> 
> Yes, the analysis is adjusting for any batch effect between your 
> replicates.
> 
> Best wishes
> Gordon
> 
> > Best regards,
> >
Maciej



More information about the Bioconductor mailing list