Mutations can affect gene expression by changing how a gene works, how much of its product is made, or whether it is turned on or off at all.
A mutation is a change in the DNA sequence. Even a small change can alter how a gene is expressed. Here are the main ways mutations can affect gene expression:
- Promoter mutations – If a mutation happens in the promoter region (the part that controls when a gene is turned on), it can increase or decrease gene activity. For example, a damaged promoter might stop the gene from being expressed.
- Coding region mutations – A mutation in the part of the gene that makes proteins can change the protein’s structure or function. This might produce a weaker, stronger, or nonfunctional protein.
- Splicing mutations – Some mutations affect how RNA is processed. If splicing is wrong, parts of the RNA may be missing or added, producing a faulty protein.
- Regulatory gene mutations – Mutations in genes that control other genes (like transcription factors) can have a wide effect, turning on or off many other genes incorrectly.
- Epigenetic effects – Some mutations can change chemical tags (like methyl groups) on DNA, which can silence a gene without changing its actual sequence.
In short, mutations can change when a gene is active, how much product it makes, or how well that product works. This can lead to visible differences in plant growth, development, or resistance to stress.