Analogues: non-homologus proteins that have similar folding site which are believed to have arisen through converges evolution.
ORF: Open Reading Frame.A series of DNA codon including a 5' initiation codon & a 3' termination codon that encodes a putative( known) gene.A DNA sequence must contain a translation start codon(usually ATG) & not exhibit any of the stop codons (usually TAA,TAG,TGA) in phase with the ATG for quite some length(at least 300 nuclotides seperate the start & stop codon).
The ORFing protocols can probably correctly identify 85% of the protein coding regions.There are a variety of situations that frequently occur where a more sophisticated approach need to use.One such approach is taken by GenMark which include
- finding very short proteins,
- resolving ambiguous cases where overlapping ORFs are predicted in different reading frames.
- to pinpoint the exact start codon(most distal ATG is not always the correct one).