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Matthias Boeck
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10
@matthias-boeck-4105
Last seen 10.2 years ago
Hello,
I'm working on the analysis of time series data (MAS5) which consists
of
two experiments (expA, expB) on two cell lines (clA, clB) (but a
similar
if not same behavior is expected and therefore they might be used as
replicates). Each experiment consists of four measurements at
different
points in time (6h, 24h, 72h and 144h) and for each of this
measurements
a control exits too. The controls are cell cultures of the same cell
line which are untreated but still can show some activity.
At the moment I try to find the differences and especially
similarities
between the two experiments in their reaction on the treatments and
wanted to use maSigPro (if you have another suggestion I would be glad
for any further advice).
I already did some calculations with the package but I'm not sure if I
got the design of the design matrix right and maybe you could be so
kind
to take a look at my matrix. Replicates are within the experiments and
I
used four dummy variables for the different experiments and cell
lines:
Time Replicate Control expB_clA expB_clB
expA_clA
expA_clB
clA_6hr_expA_ctr 6 1 1 0 0
0
0
clA_6hr_expA 6 2 0 0 0
1
0
clA_24hr_expA_ctr 24 3 1 0 0
0
0
clA_24hr_expA 24 4 0 0 0
1
0
clA_day3_expA_ctr 72 5 1 0 0
0
0
clA_day3_expA 72 6 0 0 0
1
0
clA_day6_expA_ctrl 144 7 1 0 0
0
0
clA_day6_expA 144 8 0 0 0
1
0
clB_6hr_expA_ctr 6 1 1 0 0
0
0
clB_6hr_expA 6 2 0 0 0
0
1
clB_24hr_expA_ctr 24 3 1 0 0
0
0
clB_24hr_expA 24 4 0 0 0
0
1
clB_day3_expA_ctr 72 5 1 0 0
0
0
clB_day3_expA 72 6 0 0 0
0
1
clB_day6_expA_ctr 144 7 1 0 0
0
0
clB_day6_expA 144 8 0 0 0
0
1
clA_6hr_expB_ctr 6 9 1 0 0
0
0
clA_6hr_expB 6 10 0 1 0
0
0
clA_24hr_expB_ctr 24 11 1 0 0
0
0
clA_24hr_expB 24 12 0 1 0
0
0
clA_day3_expB_ctr 72 13 1 0 0
0
0
clA_day3_expB 72 14 0 1 0
0
0
clA_day6_expB_ctr 144 15 1 0 0
0
0
clA_day6_expB 144 16 0 1 0
0
0
clB_6hr_expB_ctr 6 9 1 0 0
0
0
clB_6hr_expB 6 10 0 0 1
0
0
clB_24hr_expB_ctr 24 11 1 0 0
0
0
clB_24hr_expB 24 12 0 0 1
0
0
clB_day3_expB_ctr 72 13 1 0 0
0
0
clB_day3_expB 72 14 0 0 1
0
0
clB_day6_expB_ctr 144 15 1 0 0
0
0
clB_day6_expB 144 16 0 0 1
0
0
By using this design I end up with about 1179 probes after the first
regression step (p.vector() with q-value of 0.0001). I'm not sure if
this is a realistic amount or if it is because of the design or the
lack
of further replicates (array quality checks have already been
performed
on the data). Would a non specific filtering make sense before the
analysis?
I also considered changing the replicates column and grouped the
controls according to the cell lines but this didn't seem to alter the
results. Does the algorithm take the mean/median over all given
controls
without considering the replicate grouping? Or could this be a hint
that
the controls are quite similar and could also be combined? If the
controls are grouped together in the replicates, is maSigPro taking
the
median over those for the calculation or is this just for the
see.genes() visualization?
I'm sorry for all these questions but I haven't worked before with the
time series packages in R and I'm not sure if I use the methods
correctly.
I would be glad for any help!
Best wishes,
Matthias