Question

Check all of the statements that describe accurately the result of having a splice acceptor or donor site single-base-pair mutation in a gene.

Check All That Apply

• The primary transcript will be longer than normal.The primary transcript will be longer than normal.

• The primary transcript will be shorter than normal.The primary transcript will be shorter than normal.

• The mRNA may be longer than normal.The mRNA may be longer than normal.

• The protein encoded by the mutant gene could have some incorrect amino acids. The protein encoded by the mutant gene could have some incorrect amino acids.

• The protein encoded by the mutant gene could have more than the normal number of amino acids.The protein encoded by the mutant gene could have more than the normal number of amino acids.

• The protein encoded by the mutant gene could have fewer than the normal number of amino acids.The protein encoded by the mutant gene could have fewer than the normal number of amino acids.

• The mutant allele could be amorphic.The mutant allele could be amorphic.

• The mutant allele could be neomorphic.The mutant allele could be neomorphic.

Answer 1

First, splicing is the posttranscriptional modification of the RNAm to remove the introns(non-coding regions) keeping only the exons to be read into amino acids and therefore proteins, this RNAm is called mature RNAm

Then a splice mutation, means that a mutation occurs in the DNA changing the sequence between an exon and intron making that during splicing some exons can be left out or some introns can stay in

This kind of mutation occur in splice acceptor or donor sites, that normally control the splicing, they are located at the beginning and end of an exon

And single-base-pair mutation is a mutation where only one base pair is changed, inserted or deleted

So having a splice acceptor or donor site single-base-pair mutation in a gene, leads to the inability of the splicing to recognize that point of separation between an intron and exon, making it gloss over until the new splicing acceptor/or donor point and adding the related intron into the mature RNAm.

The primary transcript is the RNA strand made from the transcription of DNA previous to splicing, and as it is just a one pair base mutation one could say that the primary transcript is unchanged
(a clarification could be if the teacher refers to a single base-pair mutation as a point mutation that is the change of a single base affecting a single base pair, or if he refers to deletion or insertion of a base pair)

Because is possible that the acceptor/or donor splicing site is not recognized is possible that the mature RNAm would take introns making that the mRNA may be longer than normal, for the same reason the reading frame could be altered leading to The protein encoded by the mutant gene could have some incorrect amino acids and The protein encoded by the mutant gene could have more than the normal number of amino acids.

The protein encoded by the mutant gene could have fewer than the normal number of amino acids.
could also be true if the new reading frame of the aminoacids comes to a STOP codon cutting the protein short

The mutant allele could be amorphic
This means that the protein encoded by the gen has no activity
And is something that can occur

The mutant allele could be neomorphic.
This means that the protein encoded by the gen has a novel activity
this also common not so much as novel traits but cancer