Would a frame shift mutation have a more serious effect if it occured near the beggining or the end of a gene.

Question

Would a frame shift mutation have a more serious effect if it occurred near the begging or the end of a gene. EXPLAIN!

Answer 1

At the beggining, because nearly the entire secuence would be frame shifted. If the mutation ocurrs at the end, then it is possible that the small fraction of the gene afected is not critical for the gene function.

Hope this helps

Answer 2

The *likelihood* of a serious effect occurring would be greater if the mutation occurred at the beginning because after the frame shift, every codon down-stream would be altered. if the mutation is at the end of the gene, you can assume all the material before it is normal and will replicate as such.



I'm assuming you understand that different sequences of nucleotide bases specify different proteins. Codons=triplets of nitrogenous bases. There are 64 possible codons (4 bases- U,A,C,G so 4 x 4 x 4 combinations). 3 codons signal the end of the gene, these are STOP codons (UAA, UGA, UAG). If a frameshift mutation produces a stop codon at the beginning of a gene, then replication is over, and the protein that was supposed to be formed will be much shorter (that's why your question can't really bc answered with a simple yes or no).



from my medical genetics textbook:



individual amino acids, which compose proteins, are encoded by units of 3 mRNA bases, termed codons. There aew 64 possible codons and only 20 amino acids, so the genetic code is degenerate (most amino acids can be signaled by more than one codon)



one major type of mutation consists of deletions and insertions of one or more base pairs. These mutations can result in extra or missing amino acids in a protein and are often detrimental.

deletions and insertions tend to be especially harmful when the number of missing or extra base pairs is not a multiple of 3. Because codons consist of groups of 3 base pairs, such insertions or deletions can alter all of the downstream codons. This is termed a FRAMESHIFT MUTATION



Frequently, a frameshift mutation produces a stop codon downstream of the insertion or deletion, resulting in a truncated polypeptide.



i'm not sure what class you're taking but this stuff is pretty basic genetics. i know it may seem confusing at first but if you look at a diagram and understand what codons are, then frameshift mutations really make sense (I promise). i tried to explain as basically as possible. let me know if it helped at all

Answer 3

Shift Mutation

Answer 4

At the beginning. Up until the point of the frameshift, the translated amino acid sequence is correct, but after that it's nonsense sequence. If the frameshift occurs near the beginning, most of the peptide sequence will be incorrect or even truncated prematurally. The closer the frameshift is to the end, the bigger the portion of correct amino acids there will be in the sequence and the better chance the protein will have of still being able to function properly.

Answer 5

Well think about what Frameshift means. Say you have the sequence of bases: AGCTCTATCG removing the first "G", at the beginning, would give: ACTCTATCG Since three bases (a codon) code for one amino acid, you would have the transcription/translation of completely different amino acids: NO CORRECT AMINO ACIDS WOULD BE TRANSLATED! But say that instead of the frameshift mutation occurring at the beginning, it was the last cytosine "C" AGCTCTATG Notice that the first two codons (AGC,TCT) are correct even though the deletion of "C" caused a frameshift mutation at the end. In effect, we still have a frameshift mutation, but because it happened at the end of the sequence, it affects fewer codons and therefore amino acids.