<<–2/”>a href=”https://exam.pscnotes.com/5653-2/”>p>fascinating world of exons and introns.
Introduction
In the intricate landscape of genetics, exons and introns play distinct roles in shaping the genetic code. Understanding these differences is crucial for comprehending gene expression, Protein Synthesis, and evolutionary mechanisms.
Key Differences Between Exons and Introns (Table Format)
| Feature | Exons | Introns |
|---|---|---|
| Definition | Coding sequences of a gene that are translated into protein. | Non-coding sequences of a gene that are removed before translation. |
| Location | Found within the gene, interspersed with introns. | Found within the gene, separating exons. |
| Function | Carry the genetic information for protein synthesis. | Play regulatory roles and can be involved in alternative splicing. |
| Conservation | Typically more conserved across species. | Less conserved and can vary considerably between species. |
| Presence in mRNA | Present in mature mRNA after splicing. | Removed from pre-mRNA during splicing. |
| Length | Generally shorter than introns. | Generally longer than exons. |
| Evolutionary Role | Subject to purifying selection to preserve protein function. | May undergo neutral evolution or be subject to positive selection. |
Advantages and Disadvantages of Exons and Introns
- Exons:
- Advantages: Encode the essential information for protein structure and function.
- Disadvantages: Mutations within exons can directly impact protein function and lead to disease.
- Introns:
- Advantages: Provide flexibility for alternative splicing, allowing a single gene to encode multiple protein isoforms. Contribute to Gene Regulation and evolution.
- Disadvantages: Can harbor deleterious mutations that disrupt splicing or gene regulation. Their presence increases the energy cost of transcription and translation.
Similarities Between Exons and Introns
- Both are found within eukaryotic genes.
- Both are transcribed into pre-mRNA.
- Both can contain regulatory Elements that influence gene expression.
FAQs on Exons and Introns
Q: What is alternative splicing?
A: Alternative splicing is a process where different combinations of exons are included in the final mRNA transcript. This allows a single gene to produce multiple protein isoforms with diverse functions.
Q: How do introns contribute to gene regulation?
A: Introns can contain regulatory elements, such as enhancers and silencers, that influence the transcription of the gene. They can also harbor binding sites for regulatory proteins.
Q: Can mutations in introns cause disease?
A: Yes, mutations in introns can disrupt splicing or gene regulation, leading to disease. For example, mutations in introns can cause cystic fibrosis and certain types of cancer.
Q: How have exons and introns evolved?
A: Exons are generally under purifying selection to preserve protein function, while introns may evolve more rapidly due to relaxed selective pressure.
Q: What is the role of exons and introns in Genetic diversity?
A: Alternative splicing of introns generates a vast array of protein isoforms, contributing to genetic diversity within and between species.
Let me know if you would like me to elaborate on any of these aspects or answer additional questions.