What is the Difference Between ORF and Exon?

The main difference between an ORF (open reading frame) and an exon lies in their structures and functions within the context of gene expression:

• ORF: An ORF is a continuous stretch of DNA sequence that begins with a start codon (AUG) and ends with a stop codon (UAA, UAG, or UGA). It is a part of the reading frame and does not include introns. ORFs are used in genome research to indicate potential protein-coding regions in the DNA. Some short ORFs do not code for proteins but instead produce functional peptides.
• Exon: An exon is a coding sequence of a gene that encodes for amino acids and is located between the start and stop codons. Exons are parts of a gene and are found in both the gene's DNA and its RNA transcript. During the process of RNA splicing, introns are removed, and the remaining exons are joined together to form a mature mRNA. Exon sequences include both protein-coding regions and untranslated regions (UTRs). Exons are the segments of a gene that are encoded into proteins.

In summary, an ORF is a stretch of DNA sequence between start and stop codons, while an exon is a coding sequence of a gene that encodes for amino acids and is part of the mature mRNA.

Comparative Table: ORF vs Exon

The main difference between an Open Reading Frame (ORF) and an Exon lies in their role in the gene and their location within the DNA sequence. Here is a table summarizing the differences between ORF and Exon:

In summary, both ORFs and exons are nucleotide sequences, but they serve different functions within the genetic code. ORFs are part of the reading frame and can potentially encode proteins, while exons are the coding regions of a gene that encode for amino acids in the protein.