What does "isoform" and "transcript variant" differ by definition?

Question

[wangyi2412]

Are they the same? Or refer to transcript variant at different stages? Thank you!

[Devon Ryan]

We'd have to see the context. I could come up with sentences where they're the same and others where they're different.

Answer 1

[wangyi2412]

Now my understanding is:

Isoforms refers to different versions of protein from the same gene in this setting, and transcript variants refers to different versions of mRNA transcript from the same gene.

[PoGibas]

I think your understanding is correct.

You can use "isoform" to refer to different versions of protein that originate from the same locus. And "transcript variant / alternative transcript" means different version of transcript. However, this is applicable not only for mRNAs, but also for lncRNAs.

Answer 2

[cdsouthan]

Ryan is right. Usage of these and related terms "in the wild" is inconsistant (analagous to polymorphism vs variant vs mutation vs nsSNP vs engineered residue change). Most of the key databases will define their own term usage. The description "isoform" causes endless confusion, including from its historical origins as observed electrofocussing band-splitting