exon is mature RNA after intron(s) spliced out. ORF is part of exon, start from AUG to stop codon.

Exons are the parts of a gene which code for mRNA. ORFs simply refer to any DNA between a start and a stop codon, though most ORFs do not represent real genes.

If by "both have coding regionn" you mean that both contain a protein-coding region, then no, you are not correct.

Exons are the regions of an immature mRNA that are retained after splicing. They may or may not be part of protein-coding sequences (one example of the latter being the exons sitting at the 5' and 3' UTRs of a messenger RNA).

An ORF, on the other hand, is a contiguous stretch of codons, in a DNA or RNA molecule, flanked by an in-frame start codon on the 5' side and an in-frame stop codon at the 3' side. An ORF may or may not code for a protein (for that, it would have to be preceded by the appropriate translation inititation signals and, in the case of DNA-encoded ORFs, transcriptional signals). Non-protein-coding ORFs often have codon usages very different from that of the host and exhibit predicted gene products of bizarre aminoacid compositions, etc.

In the case of an intron-bearing protein-coding gene, if there is an in-frame stop codon in one of the introns, then the mature ORF only exists at the level of processed, spliced mRNA -it does not exist in the original gene.

Hope it helps!

Dear Nilam:-

ORFs:

The region of the nucleotide sequences from the start codon (ATG) to the stop codon is called the Open Reading frame.

Gene finding in organism specially prokaryotes starts form searching for an open reading frames (ORF). An ORF is a sequence of DNA that starts with start codon “ATG” (not always) and ends with any of the three termination codons (TAA, TAG, TGA). Depending on the starting point, there are six possible ways (three on forward strand and three on complementary strand) of translating any nucleotide sequence into amino acid sequence according to the genetic code .These are called reading frames.

While eukaryotic gene finding is altogether a different task as the eukaryotic genes are not continuous and interrupted by intervening noncoding sequences called ‘introns’. Moreover organization of genetic information in eukaryotes and prokaryotes is different.

Dear ...Also, see the following schematic representation...Best regard

Dear Tulsani...

Check this link:

https://www.biostars.org/p/47022/

Best Luck

i agree they both are same

thanks for explanations.

Open reading frames are naturally occurring genes especially in Eukaryotas. But Exons are processed genes whose non-coding regions, called introns have been excised and the coding regions (or exons) spliced together as one continuous gene.

ORF is the is that region which is located from start codon to stop codon(in eukaryotes).Coding region(exon) and non-coding region(intron) both can present in this region.

Exon is functional codon and ORF is a reading frame that has the ability to be translated start codon AUG and Stop codon UAA, UAG or UGA.

ORF - open reading frame -> due to intons existent, they from start to stop codon in the DNA filament, whereas

exon >> is the segment that encode a certain protein in translated process to give real amino acids..

exon is the functional part of immature mRNA while ORF is the coding region present on the mRNA in-framed starting and stop codon.