Difference Between Exons and Introns

Exons vs Introns

Exons and introns are related to genes. An exon is termed as a nucleic acid sequence which is represented in the RNA molecule. Introns, on the other hand, are termed as nucleotide sequences seen within the genes which are removed through RNA splicing for generating a mature RNA molecule.

In simple words, exons can be termed as DNA bases which are translated into mRNA. Introns are also DNA bases that are found in-between exons.

Introns and exons were discovered independently by American molecular biologists Richard Roberts and Phillip Sharp in 1977.

Introns are very much common in the genome of higher vertebrates such as human beings and mice. On the other hand, introns are unlikely to be seen in the genome of certain varieties of eukaryotic micro-organisms such as baker’s yeast but are seen in archaegal and bacterial genes.

It can also be seen that introns are less conserved which means that their sequence changes very frequently over time. On the contrary, exons are very much conserved which means that their sequence does not change rapidly over time or in-between the species.

While exons are codes of proteins, introns are not at all implicated with the protein coding. So it can be said that exons are coding areas whereas introns are non-coding areas.

The term ‘intron’ was derived from ‘intragenic region,’ a region inside a gene. Introns are also sometimes termed as intervening sequences. ‘Exon’ is a term that is derived from ‘expressed region.’ Walter Gilbert, an American biochemist, coined the term.

Summary:

1. Exons are coding areas whereas introns are non-coding areas.
2. An exon is termed as a nucleic acid sequence which is represented in the RNA molecule. Introns, on the other hand, are termed as nucleotide sequences seen within the genes which are removed through RNA splicing for generating a mature RNA molecule.
3. It can also be seen that introns are less conserved which means that their sequence changes very frequently over time. On the contrary, exons are very much conserved.
4. Exons are codes of proteins; introns are not at all implicated with the protein coding.
5. Exons can be termed as DNA bases which are translated into mRNA. Introns are also DNA bases that are found in between exons.
6. Introns are very much common in the genome of higher vertebrates such as human beings and mice but unlikely to be seen in the genome of certain varieties of eukaryotic micro-organisms.

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