Do Eukaryotes Have Introns: Why, How And Detailed Insights

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A portion or a part in the genetic material that is the DNA or RNA that does not code for proteins, is called introns.

Do eukaryotes have introns, Yes. Eukaryotic organisms have introns in them. Introns are present in between exons. Their main role is recombination in exons. They play a significant role in evolution by enhancing gene expression.

Why do eukaryotes have introns?

We know that eukaryotes are complex in structure and function.

Eukaryotes require diversity in proteins for satisfying this complex morphology. Though introns do not code for proteins, they involve themselves highly in gene expression and regulation. This is the reason the introns are present in eukaryotes.

do eukaryotes have introns
do eukaryotes have introns
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Do eukaryotes have intron splicing?

There are introns and exons in a gene. Introns are non-coding sequencing for proteins.

Yes, eukaryotes have intron splicing. The introns are detached from the sequence and the exons are spliced or connected together and then the protein synthesis takes place.

Do prokaryotes have introns?

Introns are present only in complex organisms.

Prokaryotes do not have introns in them (Absence of introns)

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Why don’t prokaryotes have introns?

Prokaryotes are simple or basic organisms.

Introns are not present in prokaryotes because prokaryotes do not possess a mechanism called post-transcriptional RNA modification, in which the introns are detached and the exons are joined or connected together.

Types of introns:

Based on the genetic biochemical and sequence analysis, introns are divided as

Spliceosome introns

Spliceosome introns are the non-coding gene part that is detached or removed by the spliceosome during post-transcriptional modification.

Self- splicing group-I

Self- splicing group-I are detached by RNA catalysis

Self- splicing group-II

Self- splicing group-II are detached by RNA catalysis

tRNA introns

tRNA introns or the Transfer RNA introns are detached by proteins.

What is the splicing process?

In the process of transcription, RNA polymerase makes copies of the gene structure including exons and introns. This is called pre-mRNA or hnRNA (Heterogeneous nuclear RNA)

Now, the introns will not code for proteins thus they need to be removed or detached. The detachment of introns and splicing or combining of the exons is called as splicing process.

mRNA Splicing:

The transcription process and the formation of mature mRNA take place in the nucleus of a cell. After this process, the mature mRNA is then transported to the cytoplasm for the translation (protein synthesis) process.

We know that the gene has introns and exons. Introns are non-coding sequences whereas exons are coding sequences that code for amino acids in a protein.

Post transcription, the end product is a pre- mRNA transcript. It has introns and exons. The structure is like the intron is attached in between 2 exons. The removal of these introns must take place before the translation process.

This is done by a protein complex called the spliceosome. This protein complex removes or cuts off the introns on the sequences and attaches all the exons together. This is called a post-transcriptional modification. Post this process, the mature mRNA molecule is transported to the cytoplasm for protein synthesis (translation).

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Summary of the splicing process:

  • Pre mRNA transcript is the product of the transcription process
  • The pre mRNA transcript has introns (non-coding sequence) and exons (coding sequence for proteins) in them.
  • For protein synthesis, that is the translation process, introns should be detached and the exons should be connected together.
  • The spliceosome is a protein complex that detaches the introns from the gene and connects the exons. This process is called post transcriptional modification.
  • Transcription and post-transcriptional modification take place in the nucleus of the cell.
  • After the detachment of introns and combination of the exons, the pre mRNA transcript is transformed into a new form called the mature mRNA which is completely ready for translation or the protein synthesis process.
  • This mRNA is transported to the cytoplasm for the translation process.

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