Wgcna -Dilemma In Choosing Soft Threshold
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11.3 years ago
pixie@bioinfo ★ 1.5k

I have two expression matrices (normalized, using dChip), with the same data except that in one of them , the expression values are log-transformed. I am trying to perform WGCNA analysis on them and getting different plots for scale independence.

First image: For the log-transformed values, some of the power-values (like 9,10) seems to approach 0.9 (red line corresponds to 0.9).

Second image: For the plot in which the data is not log-transformed, none of the power-values are falling beyond R^2>=0.9, (the red line corresponds to 0.8). I am in a dilemma as to which beta threshold I should consider and whether one should take log-transformed values or not for the analysis

data_log_transformed

data_without_log_transformed

r • 5.1k views
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In general, for microarray expression, you will want to log-transform the data before proceeding. A lot of methodologies make implicit assumptions of "normality" that will hold approximately for log-transformed data but will not for linear-scale expression values.

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thank you so much for the insight..i was really confused regarding this

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Which log transform should we apply? log2?

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