Mutations

Small-scale Point Mutations (one base pair)

Nonsense – premature stop codon, truncates the protein

***the mRNA sequence (with its U's) is what's mutated, thus mutating codons that code for specific proteins!!! here you've mutated a codon in the mRNA such that it now reads as a "STOP codon", which are either UAA, UAG, or UGA.

Missense – codes for a different AA

Silent – codes for the same AA (no change in phenotype)

Insertions/Deletions (from Transposons or errors)

Frameshift – shifts the reading frame

Splice site mutation – alters the splicing of mRNA

**splicing is a modification of an RNA after transcription, in which introns are removed and exons are joined!!

a genetic mutation that inserts or deletes a number of nucleotides in the specific site at which splicing of an intron takes place during the processing of precursor messenger RNA into mature messenger RNA. The abolishment of the splicing site results in one or more introns remaining in mature mRNA and may lead to the production of aberrant proteins.