Over Representation Vs Enrichment Analysis

Question

[jack]

Hi everyone,

would someone explain me what is the difference between representation vs enrichment analysis of genes ? is there any book or paper to read about these in more details ?

[Damian Kao]

It's the same thing really. I write a blog post about enrichment analysis recently: http://blog.nextgenetics.net/?e=94

[Devon Ryan]

They're the same thing.

[Phil S.]

FWIW: representation is just whether it is there or not. over-representation is the same as enrichment which means that, say you are working with genes, several genes from the same pathway are highly expressed or even several genes from the same pathway are diffenrentially expressed comapring two samples. In contrast, representation would than mean that genes are expressed but in no certain / specific manner.

Answer 1

[shinobee]

Over- representation methods compare sets of genes annotated to pathways to a list of those genes that are significantly deferentially expressed (DE) between two phenotypes. Enrichment methods employ a “soft” version of over-representation based on a summary statistic to characterize the level of differential expression of genes in the pathway relative to a null distribution.

[simplitia]

Examples are, Enrichment is something like GSEA whereas over-representation is something like a hypergeometric test used in panther go.