Remove batch effects
In the previous exercise, you demonstrated that the effect of batch had a larger impact on the variation compared to the effect of treatment. Fortunately, the olfactory stem cell study was perfectly balanced, i.e. each treatment was included in all 4 of the batches. Thus you can remove the variation introduced by the batch processing to increase the signal-to-noise ratio.
แบบฝึกหัดนี้เป็นส่วนหนึ่งของหลักสูตร
Differential Expression Analysis with limma in R
คำแนะนำการฝึกหัด
The ExpressionSet object eset with the olfactory stem cell data has been loaded in your workspace.
- Use
removeBatchEffectto remove the effect of the 4 batches from the data. - Use
plotMDSto plot the principal components. Label the samples by the treatment they received. - Re-visualize the principal components, labeling the samples by their batch.
แบบฝึกหัดเชิงโต้ตอบแบบลงมือทำ
ลองทำแบบฝึกหัดนี้โดยเติมโค้ดตัวอย่างนี้ให้สมบูรณ์
# Load package
library(limma)
# Remove the batch effect
exprs(eset) <- ___(eset, batch = ___)
# Plot principal components labeled by treatment
___(eset, labels = ___, gene.selection = ___)
# Plot principal components labeled by batch
___(eset, labels = ___, gene.selection = ___)