Skip to main content
Figure 1 | BMC Bioinformatics

Figure 1

From: Methodological study of affine transformations of gene expression data with proposed robust non-parametric multi-dimensional normalization method

Figure 1

Affine transformation of the red and the green signals. Left: Affine transformation of the red and the green signals for A 1 MathType@MTEF@5@5@+=feaafiart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbwvMCKfMBHbqedmvETj2BSbWenfgDOvwBHrxAJfwnHbqeg0uy0HwzTfgDPnwy1aqee0evGueE0jxyaibaieYdOi=BH8vipeYdI8qiW7rqqrFfpeea0xe9Lq=Jc9vqaqpepm0xbbG8FasPYRqj0=yi0lXdbba9pGe9qqFf0dXdHuk9fr=xfr=xfrpiWZqaaeaabiGaaiaacaqabeaadaqacqaaaOqaaGWaaiab=bq8bnaaBaaaleaatCvAUfKttLearCWrP9MDH5MBPbIqV92AaGqbaiab+fdaXaqabaaaaa@43C0@ = {(a G , a R ) = (200, 20), (b G , b R ) = (1.4, 0.8)}. The observed log-ratios as a function of the observed log-intensities for different fold changes. The blue dot-dash curve corresponds to the non-differentially expressed genes and the thinner curves above and below this curve represent log2r = ± 1, ± 2,... as labeled to the right of the curves. The lines in the gray grid, which is rotated 45 degrees (in (2A, M)), show the levels where the true signals log2 x R and log2 x G are equal to ..., -1, 0, 1,..., 16. These levels have been labeled to the left of the grid. No observations can lie outside this grid. Right: Real-world example of an affine transformation. The same slide was scanned four times at four different PMT settings. For each of the six scan pairs, the within-channel log-ratio and log-intensities were calculated. Data shown is from the red channel, which was estimated to have an offset of a R = 20.3 for all scans.

Back to article page