Frequently Asked Questions |
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Does it matter if there are stop codons in the sequence?A stop codon, by definition, is a short sequence (three nucleotides long) which signals the end of a sequence translation. In protein coding genes stop codons will not naturally occur in the middle of the sequence read because this would indicate to the messenger-RNA that the translation of nucleotides into amino acids is complete and it would result in a lot of functionless pieces of proteins. COI, the mitochondrial gene used in DNA barcode of animals, is a protein coding gene used in cellular respiration and it should no have stop-codons present in the sequence. Finding a stop codon in a sequence can be the result of many factors, most commonly it either involves an incorrect base calling from the original trace file or a shift in the reading frame of the sequence. It is important to try to fix stop codons before approving a record by confirming the base calling in the original trace file is correct and by re-running the sequence alignment. If rechecking these steps does not resolve the problem, the record can still be approved with the stop codon and it will be checked by an administrator. Back to Top |