Saturday, March 10, 2012

If a DNA nucleotide sequence is changed from ATCGACTAGCT to ATCGACTTGCT, what would happen to the amino acid?

If a DNA nucleotide sequence is changed from ATCGACTAGCT to ATCGACTTGCT, what would happen to the amino acid sequence?If a DNA nucleotide sequence is changed from ATCGACTAGCT to ATCGACTTGCT, what would happen to the amino acid?
changing an A to T in your sequence may or may not alter the amino acid produced, dending on the reading frame. Some questions i have though: There are no start codons (ATG) in your stretch of DNA so would like just this stretch translated? And if you'd like to translate from the beginning of this stretch, how come you only list 11 nucleotides rather than 12 (3 nucleotides per codon = 4 codons). Examples like that usually require visually scanning the sequence for a potential start codon.



some things that may help you though: an A to T mutation is less deleterious than an A to G mutation, for example, because the number of hydrogen bonds between these nucleotides is retained and melting temp. etc. are retained as well. This referrs to "transition" mutations.



also, if the mutation is in the FIRST position of the nucleotide it is almost always "silent"- refer to your genetic code table for this, but the amino acid that results from CCT is the same as GCT, as an example. Second and Third position mutations are often more harmful because they tend to change the amino acid produced. I cannot say which position this A to T change is, however, because i'm not sure of your reading frame, but hope these points will help.If a DNA nucleotide sequence is changed from ATCGACTAGCT to ATCGACTTGCT, what would happen to the amino acid?
The amino acid sequence will be corrupted because of the change on the 8th (A instead of T). Then the protein will not be produced.If a DNA nucleotide sequence is changed from ATCGACTAGCT to ATCGACTTGCT, what would happen to the amino acid?
Alan V is correct--it depends on the reading frame.



If your reading frame is this: ATC GAC TAG CT, then changing the TAG to TTG will change the encoded amino acid to leucine (TTG) from a stop codon (TAG) and your protein would keep being translated after it should have stopped.



If your reading frame is this: A TCG ACT AGC T, then you will again have an amino acid change to TGC (cysteine) from AGC (serine).



If your reading frame is this: AT CGA CTA GCT, the change from CTA to CTT will have no effect on the amino acid sequence because both CTA and CTT encode leucine.



You can do a google search for "amino acid codons" and get the codes for all the amino acids.

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