Date: Mon, 14 Jun 1999 12:49:33 +0200
From: "Gatherer, D. (Derek)" <D.Gatherer@organon.nhe.akzonobel.nl>
Subject: RE: Measuring Memes
To: "'memetics@mmu.ac.uk'" <memetics@mmu.ac.uk>
Raymond:
I am still a bit confused. Could you provide a discrete example of a gene
that is not an ORF?
Derek:
RNA genes, ie. rRNA, tRNA and snRNA genes have no ORFs in them because they
don't code for protein.
In any case a protein-coding gene is more than just an ORF, although the ORF
has to be part of the spliced mRNA transcription product, there are also 5'
and 3' UTRs and polyA tails, and at the genomic level there are promoters,
enhancers, introns etc.
Also scanning for ORFs has proved to be a poor gene-prediction algorithm in
the Human Genome Project for the annoyingly technical reason that single
base sequencing errors can cause ORFs to go out of frame. Thus we have to
use other algorithms for gene prediction. (I still do an ORF scan for my own
satisfaction, but only once I think I've found the exon boundaries by
another method)
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