Difference Between Exons and Introns

Exons and Introns are two components of DNA. Exons are the parts of DNA that contain the instructions for making proteins, while introns are parts of DNA that don’t code for anything.

The differences between exons and introns can be broken down into three categories: size (in nucleotides), function, and position within the genome. Let’s take a look at each category one by one. In general DNA is composed of components called exons and introns. Exons are the bits that make up our genes and Introns are the sequences at the beginning and end of our genes.

DNA is made up of molecules called nucleotides, each consisting of a pentose sugar (ribose or deoxyribose) attached to one nitrogenous base, usually adenine, guanine or cytosine. The sequence seems random but when plotted out it reveals a pattern that nature uses to create such things as animal and plant cells with identical DNA despite vastly different structures.

The length of DNA varies between genes but within a gene it is usually either 30,000 bases, 90% of which are exons, or 21,000 bases, 90% of which are introns.

An Intron is a part of DNA that is not needed in the final structure of the gene. If an intron was to be removed from a chromosome then the resulting piece of DNA would be shorter than what is required to make a functional protein. This can happen if there are duplications on the chromosomes where one copy has an intron that gets cut out by a transposon and another copy doesn’t have an intron that gets cut out by the same transposon.

What is Exon?

Exon is the section of DNA in between two lines. It is made of up nucleotides and has a coding sequence. The coding sequence is translated into amino acids which form a protein. Exons contain the information that determines how different parts of an organism develop, such as its hair or skin colour. Exons are often used to define when two proteins have the same function. If a protein was made up of exons that were in different positions relative to each other, then the function of the protein would be different.

What is Intron?

Intron (intervening sequences) is the section of DNA found between exons. It does not code for any proteins, but it does code for intracellular RNA that plays a role in mRNA being translated into proteins. Introns are sections of DNA that are not used in the final structure of a gene. If an intron was to be removed from a chromosome then the resulting piece of DNA would be shorter than what is required to make a functional protein. This can happen if there are duplications on the chromosomes where one copy has an intron that gets cut out by a transposon and another copy doesn’t have an intron that gets cut out by the same transposon. An intron is a section of DNA which is not translated into proteins. It has no known functions in any organism and is spliced out as part of the process that creates messenger RNA (mRNA). The mRNA carries information from the gene to the ribosome which translates it into a protein.

Difference between Intron and Exon

• Exon is the section of DNA that contains protein coding sequence
• Intron is the section of DNA which does not contain a gene coding sequence
• Introns are deleted by transposons
• Exons can be spliced out by introns
• Exon breaks during transcription or replication while Intron does not break during transcription or replication of Protein Genes
• Introns are removed or spliced out of pre-mRNA while exons are retained
• Exon contains a protein coding sequence while Intron codes for the intracellular RNA
• Exon is the section of DNA that makes up a gene while intron is not even involved in genetic makeup
• The exon puts together the final product which is a protein and the intron only codes for an RNA message which is used by the cell to make proteins
• Introns are more abundant as compared to exons in the human genome

Conclusion

So now we can clearly understand the difference between exon and intron. As you can see, exon contains the protein coding sequence while intron doesn’t contain gene coding sequence. There are many types of introns like L1, SVA, SINEs, LINEs etc. that involve duplications of DNA segments. Introns are also known as intervening sequences found inside a gene and are removed by transposons. An exon breaks during transcription or replication while an intron does not break during transcription or replication of Protein Genes.