[BioC] No replicates and differential analysis !!

Nicolas Servant Nicolas.Servant at curie.fr
Wed Jan 25 15:19:40 CET 2006

Thanks for your answer,
But in this case, i have to choose a fold change threshold ! And it is 
supported that the FC tends to be greater at low expression levels.
For instance a FC greater than 2 for expression values near 50 is 
readily seen, but it is low probability to observe FC greater than 2 for 
expression values near 1000
So i would like to use a more robust approach.

Nicolas S.

Sean Davis wrote:

>On 1/25/06 8:34 AM, "Nicolas Servant" <Nicolas.Servant at curie.fr> wrote:
>>Does anybody know a R package or function to compare expression level
>>(affy data) of two groups with no replicates in each group ? In fact,
>>just compare one array to an other.
>>The purpose is to find differentially expressed genes.
>>We cannot used statistical test (not enougth replicates), but we can
>>used graphical approach based on scatter plot, and outliers detection
>Simply take array A and divide it by array B.  Then rank the genes by those
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>Bioconductor at stat.math.ethz.ch

Nicolas Servant
Equipe Bioinformatique
Institut Curie 
26, rue d'Ulm - 75248 Paris Cedex 05 - FRANCE

Email: Nicolas.Servant at curie.fr
Tel: 01 44 32 42 75

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