Absolute Copy Number And Relative Copy Number

Question

[xiguoyuan]

Hi, I am working on copy number alteration analysis. What I got from TCGA project is .CEL datasets, which is transferred to log2 ratios after normalization and segmentation processes. What is the relative copy number and absolute copy number?

Answer 1

[Devon Ryan]

What is the relative copy number and absolute copy number?

It's the same as relative vs. absolute anything. See, for example, this link. In short, absolute always refers to the actual number of something. So, 4 copies of a genes in patients vs. 2 copies in normal controls would be a typical example. The relative copy number, then, would be that there are twice as many copies in patients vs controls.