Yes, DNA can go wrong.
While DNA replication is generally accurate, mistakes can occur. These mistakes, often called mutations, happen because:
- Polymerase errors: DNA polymerase, the enzyme responsible for copying DNA, sometimes inserts the wrong nucleotide or adds too many or too few nucleotides. This is a primary source of error during DNA replication.
- External factors: Environmental factors like radiation, certain chemicals, and viruses can damage DNA. This damage can lead to errors if not properly repaired.
How DNA Mistakes Are Handled
Fortunately, cells have various mechanisms to address these errors:
- DNA Repair Processes: Multiple enzyme systems patrol DNA and fix most of the mistakes. These processes recognize damaged or mismatched base pairs and repair them using an undamaged strand as a template.
Types of DNA Mistakes:
Here are some examples of how DNA can go wrong:
| Type of Mistake | Description | Example |
|---|---|---|
| Substitution | A single nucleotide is replaced with another. | An 'A' replaced with a 'G' |
| Insertion | An extra nucleotide is added to the sequence. | Adding an extra 'T' in a sequence |
| Deletion | A nucleotide is removed from the sequence. | Removing an 'C' from a sequence |
| Frameshift | An insertion or deletion that alters the reading frame of the genetic code. | An insertion that leads to a completely different amino acid sequence |
Consequences of DNA Mistakes:
- Most DNA mistakes are corrected, and some mistakes have no noticeable effect.
- However, some errors can have significant consequences including:
- Genetic diseases: Many diseases arise from mutations in critical genes.
- Cancer: Uncorrected DNA damage can lead to uncontrolled cell growth.
- Evolution: Genetic changes, including errors, drive the process of evolution.
While these errors are a normal part of cellular function and most are corrected or do not have noticeable impacts, it's important to note that the potential for errors is there. DNA, though usually precise, is not infallible and this can have impacts on an organism.
