"The differences in pre-mRNA splicing that results in an altered pattern of exon inclusion" is most likely to have contributed to this phenomenon.
Option: C
Explanation:
The expression of the eukaryotic gene requires several stages and can be regulated by several of them. Different genes are controlled at different locations and it is not unusual for a gene to be controlled at multiple steps, especially a significant or powerful one.
- In accessibility of Chromatin the chromatin structure includes DNA and can be regulated by its assembling proteins. More free or 'relaxed' chromatin allows a gene more transcriptible.
- For many genes transcription is a key regulatory point. Its factor protein sets bind to unique DNA sequences within or near to a gene and encourage or suppress its transcription into an RNA.
- It is possible to control the splicing, capping, and attaching a poly-A tail to an RNA molecule, and thus exit the nucleus. Specific mRNAs might be produced by alternative splicing from the same pre-mRNA.