Gene mutation

Mutations in non-coding regions
Now let's turn to those mutations that occur in regulatory and other non-coding
sequences. Those parts of a gene that are not protein coding contain a variety of
crucial functional sites. At the DNA level, there are sites to which specific
transcription-regulating proteins must bind. At the RNA level, there are also
important functional sequences such as the ribosome-binding sites of bacterial
mRNAs and the self-ligating sites for intron excision in eukaryote mRNAs.
The consequences of mutations in parts of a gene other that the polypeptide-coding
segments are difficult to predict. In general, the functional consequences of any
point mutation (substitution or addition or deletion) in such a region depend on its
location and on whether it disrupts a functional site. Mutations that disrupt these
sites have the potential to change the expression pattern of a gene in terms of the
amount of product expressed at a certain time or in response to certain
environmental cues or in certain tissues.
It is important to realize that such regulatory mutations will affect the amount of the
protein product of a gene, but they will not alter the structure of the protein.
Genetica per Scienze Naturali
a.a. 08-09 prof S. Presciuttini