Which statistical test should be used for comparison of a single gene expression?

Question

[Tonkatsu]

If I have a single replicate per condition and I am trying to see if the differences in gene expression ( for a single gene) are significant between conditions what would be the correct test to use? Also out of curiosity, if some conditions have a single replicate while others have more than one, which test should be used then?

Thank you

[Ram]

You're talking about comparing two numbers in a statistically significant way. I don't think that's possible.

[Shred]

For the second question, you may be looking for a t-test. Read more here https://compgenomr.github.io/book/how-to-test-for-differences-between-samples.html

Answer 1

[Jean-Karim Heriche]

Without replicates, you don't get any idea about the underlying distribution of values so you can only say if two numbers are equal or if one is greater or smaller than another. If you have replicates, you can get an idea of the underlying distribution for that condition and then you can try to build a prediction interval but unless you can assume some parametric distribution (e.g. the data is normally distributed), in the non-parametric case, you'll probably need quite a few replicates.