An open reading frame (ORF) is the DNA sequence between a start codon (ATG) and a stop codon (TAA, TGA and TAG). A long ORF suggests it could be a protein coding gene. In prokaryotes, like everyone’s fav bacteria E. coli, they are usually 1000base pairs so making a protein of about 350 amino acids. Many short ORFs are present and even some long ones may not make a protein. Even when quiet positive that an ORF makes a protein (codon bias is correct etc) we may not know what it does. It could only be expressed in a situation that cannot be replicated in the lab. Of course everything becomes more complicated in eukaryotes like us! Our ORFs are interrupted by introns so between the start and stop codon extra start and stop codons may be present in the intron so finding genes are a lot more difficult. So sequencing cDNAs (mRNA made into DNA) can show us where genes are in the genome. We can match up sequences from cDNAs (like ESTs) to the genome and find genes. This could show up pseudogenes so we need to check the gene is expressible.
So this blog is a place for us to talk about allsorts but all we know anything is about is biology so I suppose it will be mainly about that. It is an ‘open’ place to talk about it (get the pun, open…yeah I know I’m funny).
4 comments:
Brilliant James, very professional, and you even managed to put ESTs in it, Rahman would be proud of you. Is good to know that our tutorials last year had good repercursions...
I did only put EST in for you lol.
it is a bit of a boring basic post but i thought it was needed. promise to write a good one soon.
write something about apoptosis... In fact, a challenge for you: post about the 100 ways of classifying apoptosis, necrosis and other fancy names for cell death without making it boring... up for the challenge? :-)
one problem with that, i dont actually know the answer, when i do i will make it.
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