2007-02-11 23:12:00 · 5 answers · asked by JAGANATHAN Mk 1 in Science & Mathematics ➔ Biology
Yes, it is possible to identify a gene from a DNA sequence. The first step is to identify an open reading frame, meaning that there is a start codon, which are the bases ATG and somewhere down the line a STOP codon. This potential open reading frame would also need to have the hallmarks of a promoter sequence upstream or 5' to the start codon which usually includes a TATAA box anywhere from 200-1500 bases upstream of the start codon. The 3' untranslated DNA usually has some hallmarks to it also.
So yes, it is possible to identify a gene without knowing it's function. Depending on the organism you are looking at, however, it is possible to identify a pseudo-gene, or something that has all the characteristics of a gene, but does not actually function as one, so while it is possible to identify one, without testing it, you don't know if it really is one or not.
2007-02-12 01:46:19 · answer #1 · answered by btpage0630 5 · 0⤊ 0⤋
The question is not too clear, so I may not give you what you want.
If you mean 'can a particular sequence of DNA be recognized as probably being a gene, rather than junk?', then usually the answer is yes. If it is a gene then there will be a long (100s or 1000s) stretch of bases that can be translated into a protein (an open or unidentified reading frame). Also, if it is a real gene then there will a start codon with several regulatory sequences upstream. If it is junk then there will be potential STOP codons at frequent intervals, which would prevent any sizable protein from being coded.
2007-02-12 07:34:17 · answer #2 · answered by Pierian 4 · 0⤊ 0⤋
If you are just trying to identify any and all genes in a DNA sequence you can use computer programs to search for potential open reading frames (ORFs), which are simply stretches of bases with a start codon in good translational context followed by a significant number (usually 50 or higher, but you can set the parameters) of in frame codons before a stop codon.
If you are looking for a specific gene the question gets a lot harder. You could try to search for homologues in genbank, and use that as a source of amino acid or nucleotide seqeunce to blast against your DNA sequence of interest. Alternatively, you need to try to sort your gene of interest out of the background using a technique like differential display.
2007-02-12 09:08:56 · answer #3 · answered by floundering penguins 5 · 3⤊ 0⤋
A DNA sequence in codons make amino acids. These amino acids make up genes, I think. If you know what amino acids make up which genes, then you can identify a gene from a DNA sequence.
2007-02-12 11:00:49 · answer #4 · answered by Shockwave48 2 · 0⤊ 3⤋
I think a dna sequence doesn't enough for identifying a gene.
2007-02-12 08:20:37 · answer #5 · answered by ~ Cattail ~ 2 · 0⤊ 3⤋