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Hidden Genes: A New Frontier in Genetics
Context:
A new study by Columbia researchers reveals that bacteria can create free-floating and temporary genes, suggesting that similar genes might exist outside our genome.
More on News:
The research reveals that bacteria can create genes that do not reside in their chromosomal DNA. Instead, these genes exist as free-floating entities, adding a new dimension to our understanding of genetic regulation and functionality.
New Insights into Bacterial Genetics
- Genetic code was first deciphered in the 1960s, scientists have operated under the assumption that the chromosome contains the complete set of instructions for cellular functions.
- This linear model, which equates genes to fixed sequences within our genomes, was thought to apply universally across life forms, from bacteria to humans. However, a recent study challenges this notion.
Key Highlights:
- The study focused on a bacterial defence system that involves an unusual mechanism: a piece of RNA and a reverse transcriptase enzyme.
- Unlike typical bacterial defence systems that degrade viral DNA, this system synthesises DNA from an RNA template—a process previously considered unconventional.
- They developed a novel technique to identify DNA produced by the reverse transcriptase.
- Results showed that the DNA was long and repetitive, containing multiple copies of a short sequence from the RNA molecule.
- The RNA folds into a loop, and the reverse transcriptase creates repetitive DNA by travelling repeatedly around this loop.
- This gene codes for a protein named Neo, which plays a critical role in the bacterial antiviral defence system.
- When a virus infects a bacterium, the Neo protein prevents viral replication and protects neighbouring cells.
Implications for Human Genetics:
- Similar free-floating genes might exist in humans and other higher organisms. If confirmed, this would represent a major shift in our understanding of gene location and function.
- These extrachromosomal genes could be present only in specific environments or developmental contexts, providing essential information for normal physiological processes.
Future Directions and Applications:
- Reverse transcriptases are already used in gene editing technologies, such as CRISPR, which have seen clinical trials for conditions like sickle cell disease.
- The new reverse transcriptase produces the Neo protein, and may offer improved options for genome editing and gene therapy.
- The researchers believe that bacteria may harbour a wealth of reverse transcriptases with unique properties that could lead to innovative biotechnological applications once their functions are fully understood.
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