Why Are Some mRNA Transcripts Bigger Than Others?

[plexus0208]

Homework Statement

After isolating the same mRNA transcripts of the same gene, why are some transcripts bigger than others?

Homework Equations

The Attempt at a Solution

 

[Ygggdrasil]

Consider what happens to mRNAs after they are initially synthesized.

 

[plexus0208]

polyA tail?

 

[Ygggdrasil]

Yes, the poly(A) tails can be of differing length (e.g. some poly(A) tails may have undergone more degradation than others). The mRNAs can also be alternatively spliced resulting in differently sized transcripts.