what are Differentially Expressed Genes?

Question

[SKY]

What are Differentially Expressed Genes(DEGs)?

Are the genes that are only expressed in treated/diseased condition (and not in control) considered as DEGs?

[SKY]

Biostars is a savior for many newbies like me. I thank all the creators of this platform.

Answer 1

[Papyrus]

"Differentially expressed" is just an arbitrary label we use to describe particular results. Most often, it refers to genes for which, in "some" comparison, a statistically significant change was detected. However, how the comparison is made, and between which groups (and even whether the genes are truly "significant" by some statistical parameter) will depend on the particular study.

I would say that in most literature, DEGs usually are genes with evidence of increase or decrease in expression in some condition as compared to other. (So, not "expressed in one condition as opposed to the other" as you propose). But again, DEGs really are what each paper defines them to be in their particular scenarios.

[Friederike]

Well put! I'll just add that seeing what OP asked, I'd put the emphasis on genes with evidence of increase or decrease in expression in some condition as compared to other.

[Papyrus]

yes, you're totally right!

[SKY]

Biostars is a savior for many newbies like me. I thank all the creators of this platform.