GAUTAM ORF FINDER
An ORF (Open Reading Frame) finder is a web-based program written in perl script in 2008 to find Orf present in a DNA sequence. Based on your input, GAUTAM ORF FINDER will firstly generate complimentary DNA sequence. Secondly, to get Orf the program will generate reverse complimentary DNA sequence. Finally, the program generates 6 reading frames out of which there are 3 reading frames from DNA sequence and 3 reading frames from Complimentary DNA sequence and then it displays Orf positions in all reading frames.
For example, if you input DNA sequence:
5’ TCAATGTAAC 3’
Then the program will generate complimentary DNA sequence i.e.
5’ AGTTACATTG 3’
Now to get ORF the program will generate reverse complimentary DNA sequence i.e.
3’ GTTACATTGA 5’
Now the program will display 6 reading frames out of which there are 3 reading frames from DNA sequence and 3 reading frames from Reverse complimentary DNA sequence such as:
1st Reading frame : TCAATGTAAC
2nd Reading frame: CAATGTAAC
3rd Reading frame: AATGTAAC
4th Reading frame: GTTACATTGA
5th Reading frame: TTACATTGA
6th Reading frame: TACATTGA
As there are following-
START CODONS: ATG, GTG, TTG
STOP CODONS: TAA, TAG, TGA
So if you consider 1st Reading frame i.e.
Then it can be concluded that ORF will be present between ATG & TAA because ORFs are located between the start-code sequence (initiation codon) and the stop-code sequence (termination codon).
In the same way ORF FINDER 2008 will find ORF in other reading frames and at last the largest ORF will be the one which has the largest distance between START CODON & STOP CODON.