Different lengths of genes expressed

[icakeov]

I was wondering whether it can ever happen that only a certain "length" of the same gene gets expressed in different species? Or perhaps even within the same species? (Without it being a random mutation)

Basically, can a part of a gene be expressed, and still have some functionality in the organism, rather than get scrapped as a mis-folded protein?

 

[BillTre]

(Not sure what you mean in the first part of the question.)

can a part of a gene be expressed, and still have some functionality in the organism, rather than get scrapped as a mis-folded protein?

Yes that can happen.

Some mutations can result in a truncated protein by inserting a stop codon into the protein encoding sequence. This can cause a non-functional protein, but not always. Some can still have function. Depends how much of the protein is removed and how important the missing part was to its function.

In addition, there are often (in vertebrates) splicing alternatives where the mRNA can have some of this part or some of that part removed, leading to proteins of different lengths or have differences in different parts of the protein.

 

[icakeov]

Thanks BillTre! Totally what I was asking.
The two questions are essentially supposed to be the same, glad I reworded it in the second part.
Would these "similar" proteins that are built out of splices still have similar "active sites" that attract similar or same substrates?

 

[BillTre]

Would these "similar" proteins that are built out of splices still have similar "active sites" that attract similar or same substrates?

It depends on the particular gene.
The mRNA can use one bit of sequence or another at different places to make the final protein.
The different parts can be quite similar or quite distinct.

Another added complexity occurs after the protein is made. Enzymes can come along and cut out specific parts of the protein to make one or more smaller parts that are the final products. Precursors for Proopiomelanocortin is a example of this, a precursor protein that is cut up into several hormone acting peptides .

 

[icakeov]

Great, thank you!