Entering edit mode
Md.Mamunur Rashid
▴
260
@mdmamunur-rashid-3595
Last seen 10.2 years ago
Dear Wei,
Thanks for your reply. I know it's a long email, but I tried to give
details about the raw data
Please have a look when you have some spare time.
1. About the raw data :
-----------------------
Yes this arrays are from the same bead chip. The experiments were done
by three individuals (each
person conducted experiments with 3 beadchips each consisting 12
arrays, 96 intotal). I think this
is the reason for high variance among 3 sets of arrays. 1-32, 33-64,
65-96. But after normalization
("quantile"-lumi package) the data looks quite normal.
I have attached two snapshot of boxplot of the raw data and normalized
data.
A. Normalized data -http://www.esnips.com/doc/ad4c8a55-2166-49
11-8510-df81eaea63df/data_96_illumina_norm
B. Raw data - http://www.esnips.com/doc/0a965715-b5ec-44da-
b64c-4d025c63827b/96_illumina_raw
If you look at the two snapshots above : Expression range for raw data
in most cases are below 6. But
after normalization it came slightly above 6. Is it possible at all or
something is going wrong during
the normalization.
One question here. Does illumina data require intra-array
normalization.?? To the extent of my little
study I know that they do not need it as it is already done. Please
let me know what do you think.
2. About Arrayweight
--------------------
As you can see below the the results have not been improved much
compare to the old topTable result.
1. Do you think this high variance in arrays are causing this
problem.???
2. Does fitting the arrayweight in the linear model along the
normalized object drops the downweighted arrays
or that needed to be done manually??
3. Pre-processing with beadarray
--------------------------------
I have the done the same analysis using beadArray package(data
import and pre processing) and had the similar
result. So there can be two possibilities which can lead to this
problem.
A. Problems in the raw data.
B. Or I am doing a wrong linear modeling of the data.(as that is
the common part in the both analysis)
I have attached my code fragment here. please have a look:
*** What are the other bio packages/tests I can use for
identifying differentially expressed genes>?
Thanks in advance
best regards,
Md.Mamunur Rashid
Code Fragment
-----------------------------------
About fitting the weights : I have done the following
data_96_nuId_E holds the normalized object
data_96_sampleType<- c("I","I","I","I","I","S","S","S","I","C","S","S"
,"C","I","C","I","I","I","I","S","I","S","I","S","C","C","S","I","C","
S","I","S","S","C","C","S","S","I","I","I","S","I","S","I","I","C","I"
,"C","S","C","I","I","S","C","S","S","S","C","C","I","S","S","C","I","
I","C","C","S","S","S","C","C","S","I","C","C","C","S","C","C","I","I"
,"C","S","C","C","C","S","C","S","C","I","I","S","I","C")
data_96_design<- model.matrix(~0+data_96_sampleType)
colnames(data_96_design)<- c('C','I','S')
## filtring out the non-expressed genes
presentCount<- detectionCall(data_96_raw_nuID)
data_96_Matrix<- data_96_Matrix_old[presentCount> 0, ]
data_96_probeList<- rownames(data_96_Matrix)
arraw_E_96<- arrayWeights(data_96_nuID_E,data_96_design)
data_96_contrast<- makeContrasts (C-I,I-S,S-C,levels=data_96_design)
fitw_nu_96<- lmFit(data_96_Matrix,data_96_design,weights=arraw_E_96)
fitw_nu_con_96<- contrasts.fit(fitw_nu_96,data_96_contrast)
fitw_e_nu_96<- eBayes(fitw_nu_con_96)
topTable(fitw_e_nu_96,coef=1,adjust="BH")
ID logFC AveExpr t P.Value
adj.P.Val
3564 oEptU7gl5ULB7ghAf4 -0.11681240 6.341389 -4.749578 7.204301e-06
0.1484950
3900 cUSJ2.kBKqPAk0eZPY 0.31230030 6.881320 4.561405 1.514923e-05
0.1561280
10705 uHk1A0FNxKMV0k7a50 -0.13640964 6.616042 -4.197525 6.070562e-05
0.2895144
14598 WokXUp_QIC4pd_s1.U -0.09998362 6.342947 -4.111694 8.338387e-05
0.2895144
4324 xXLgIpJ_AeI7gRNJ_U 0.11230531 6.478843 4.072272 9.634276e-05
0.2895144
6399 HHteoiUdSJz9wh.e64 0.16605833 7.322017 4.034305 1.106350e-04
0.2895144
13446 x65aXRiHVTIIUQiv00 -0.23601528 6.487643 -3.986742 1.314198e-04
0.2895144
13445 HrlpdGIdVMghRCK.TU -0.20278431 6.470915 -3.986291 1.316337e-04
0.2895144
16912 BgFUhUUgIQu3JDl_sU 0.11902363 6.815447 3.978352 1.354541e-04
0.2895144
9813 NAv6twbtRAh7QuCDro 0.09999394 6.511654 3.958318 1.455733e-04
0.2895144
B
3564 3.5478599
3900 2.8790555
10705 1.6341835
14598 1.3504633
4324 1.2214803
6399 1.0980586
13446 0.9445695
13445 0.9431198
16912 0.9176269
9813 0.8534456
About fitting the arrayweights in the linear model :
previously I have produced arrayweights
On 09/21/2009 12:59 AM, Wei Shi wrote:
> Dear Mamun:
>
> Sorry for replying to you late. I am just back from the holiday.
>
> Some of your arrays have pretty low weights. Arrays 37-42 have
> weights of around 0.2. Are these arrays from the same bead chip? You
> can try put array weights in the linear model fitting to see if you
> can get DE genes.
>
> Cheers,
> Wei
>
> Md.Mamunur Rashid wrote:
>> Dear Wei,
>>
>> Thanks again for your reply. I have measured the array-weights
using limma's arrayweights() method. There seem to be
>> a good amount of variation among the raw data. But I am not really
sure whether it is acceptable or not??.
>>
>> But the normalized data have an average value of 1.022609
>> with min = 0.5641711 max =1.417277.
>>
>> Also 2 more question :
>>
>> 1. can you explain a bit more about how can I filter out the genes
whose detection p-values
>> are larger than cut-off (e.g. 0.01) in all samples??
>> 2. how can I check batch effect and chip effect in the raw data.??
>>
>> Thanks in advance. Any help from anyone also is appreciated.
>>
>> regards
>> Mamun
>>
>>
>> Below is the result from arrayWeigts() method.(Table 1 (weights for
raw data) Table 2(weights of normalized data))
>> *** Also attached a text file with the weights.
>>
>> ArrayWeight of Raw Data:
>>
>> arrayWeights(data_96_raw,data_96_design)
>>
>>
>> 1 2 3 4 5 6
7 8
>> 3.2861102 0.6091478 2.6927503 2.2778201 2.4391841 0.7802437
1.1378995 0.5714981
>> 9 10 11 12 13 14
15 16
>> 0.8091165 0.5260511 0.7565424 0.8354660 0.2929977 0.4950789
0.4512856 0.1283279
>> 17 18 19 20 21 22
23 24
>> 0.6713553 0.6275333 0.5441217 0.2711778 0.7278274 0.3323277
0.5786381 0.7375983
>> 25 26 27 28 29 30
31 32
>> 0.5793944 0.4018671 0.6658730 1.6805341 0.7210032 1.2802383
0.8902326 0.6715769
>> 33 34 35 36 37 38
39 40
>> 0.2959048 0.8854763 0.7587111 1.5067705 0.1766820 0.1639351
0.1739882 0.1833592
>> 41 42 43 44 45 46
47 48
>> 0.2443871 0.2188281 0.2945594 0.2607380 0.3419603 0.5932775
0.3396003 0.7229979
>> 49 50 51 52 53 54
55 56
>> 0.8274153 1.7944800 0.8306203 1.0738534 1.5052515 2.9798751
2.0836544 1.5010941
>> 57 58 59 60 61 62
63 64
>> 2.3827591 2.7575819 1.5967670 3.3397084 2.0576009 2.9660262
3.8417611 1.3469622
>> 65 66 67 68 69 70
71 72
>> 1.7334743 2.7855044 4.5417142 3.2551286 3.9634064 3.8054377
3.8020479 4.2732205
>> 73 74 75 76 77 78
79 80
>> 0.2659556 0.3440704 0.6404601 0.8697107 1.0736648 0.8835502
0.9912724 0.4334270
>> 81 82 83 84 85 86
87 88
>> 0.8801461 1.0309162 2.5352693 1.8366521 2.5501944 4.5388081
4.2603196 1.7665255
>> 89 90 91 92 93 94
95 96
>> 2.5511084 2.3867529 4.0237262 2.1647555 3.3101943 2.5863558
1.8618118 0.2397050
>>
>>
>>
>>
>> Array Weights of normalized data:
>>
>> 1 2 3 4 5 6
7 8
>> 0.8908085 1.1978748 1.1454450 1.0215452 1.3605699 0.8141813
1.4172765 1.2958270
>> 9 10 11 12 13 14
15 16
>> 1.0522608 1.2562065 1.3531495 1.1489293 1.0596229 1.1217643
0.9156484 0.6705476
>> 17 18 19 20 21 22
23 24
>> 0.9643412 1.2120423 1.0672521 0.9983735 0.8096782 0.9379575
1.0493924 0.7614746
>> 25 26 27 28 29 30
31 32
>> 1.1573255 1.2735353 1.3795986 0.9499952 1.3602425 1.2549726
1.1772558 1.4158351
>> 33 34 35 36 37 38
39 40
>> 1.3659316 1.0658774 1.3185647 0.9017821 0.7915704 0.6326567
1.0325512 0.6812818
>> 41 42 43 44 45 46
47 48
>> 1.0142990 1.1921695 1.1476346 0.8255798 1.2012711 1.1893762
0.9367947 1.1594407
>> 49 50 51 52 53 54
55 56
>> 1.1072266 1.0561352 0.8488650 1.1756689 1.0554286 0.9326934
1.2836555 0.9665945
>> 57 58 59 60 61 62
63 64
>> 1.3293081 1.3027377 1.3459009 1.2834152 0.9657114 1.0041629
0.8823282 0.6843356
>> 65 66 67 68 69 70
71 72
>> 0.8883121 0.9374396 0.9799943 0.9733364 1.2045700 1.0693506
0.7730626 0.9408430
>> 73 74 75 76 77 78
79 80
>> 0.6685933 1.0492289 0.9952222 0.9690452 1.0150076 1.0148188
0.6687192 0.5641711
>> 81 82 83 84 85 86
87 88
>> 0.7872238 0.8793660 0.8553373 0.9662603 0.6143880 1.0340769
0.9842437 0.6626941
>> 89 90 91 92 93 94
95 96
>> 1.0270788 0.8590296 1.0807271 0.8162435 1.0398548 0.8993595
1.2094240 0.5715857
>>
>>
>>
>>
>>
>>
[[alternative HTML version deleted]]