- Reading frame
In
biology , a reading frame is a contiguous and non-overlapping set of three-nucleotide codons inDNA orRNA . There are 3 possible reading frames in amRNA strand and six in a double strandedDNA molecule due to the two strands from which transcription is possible. This leads to the possibility of overlappinggene s and there may be many of these in bacteria.cite journal | author = Johnson Z, Chisholm S | title = Properties of overlapping genes are conserved across microbial genomes | journal = Genome Res | volume = 14 | issue = 11 | pages = 2268–72 | year = 2004 | pmid = 15520290 | doi = 10.1101/gr.2433104] Some viruses e.g.HBV andBYDV use several overlapping genes in different reading frames.In rare cases a translating
ribosome may shift from one frame to another, atranslational frameshift . It is distinct from aframeshift mutation as the nucleotide sequence (DNA or RNA) is not altered only the frame in which it is read.An
open reading frame (ORF) is a reading frame that contains astart codon , the subsequent region which usually has a length which is a multiple of 3 nucleotides, and end with astop codon .References
ee also
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Genetic code
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