Answer:
DNA transcription is the process that generates a complimentary strand of messenger RNA, mRNA, from the DNA template strand. Things do not always go perfectly and some errors might slip through the error checking and correcting mechanisms in DNA transcription.
Explanation:
An uncorrected error in DNA transcription can lead to a potential change in amino acid sequence in the protein produced from the transcription. If any change in amino acid sequence does occur, it could either result in a disadvantage to the organism or may result in an advantage. Random mutations and responses to environmental pressures are aspects thought to drive the evolutionary process. Disadvantages could be reduced ability of the coded protein to perform its metabolic role or complete failure to perform. Advantages could be a completely new protein that could help the organism respond to an environmental change, or it may just improve the functionality of the protein somewhat. Or nothing at all will happen.
But there are measures that help lessen the effects, especially potential catastrophic effects, of random mutations. One is the redundancy built into the translation stage such as having 64 possible 3-base pair sequences coding for amino acids when there are only 20 amino acids. For example, if an error occurred in the last base of a sequence codon coding for glycine, nothing would happen since all four possible combinations (GGA, GGC, GGG, and GGU) all code for a glycine amino acid. An error in one of the first two positions though is another story. Another is there are large regions of DNA that simply are place holders separating gene coding sequences or code for sequences that will be cut out of the final protein during post-translational modification which some proteins undergo after translation. A change in these "nonsense" DNA regions would have no effect at all on functional protein production.
Thanks to the error checking and correction mechanisms in DNA transcription, errors are kept to a minimum.
