Switching genes on or off can help a cell carry out its specific functions. Different types of cells, such as muscle cells and brain cells, have different patterns of genes active at different times.
One of the ways to regulate which genes are active at what time is DNA methylation.
When a gene is switched off, proteins add chemicals known as methyl groups at certain points in the DNA sequence. Only the bases C (cytosine) and G (guanine) are able to have methyl groups attached to them.
These methyl groups act as signals that the gene is switched off or silenced, and can not be transcribed into a protein.
This type of DNA alteration – one that does not change the underlying DNA sequence – is known as an epigenetic modification. Epigenetics is a growing field of study, as scientists are beginning to uncover more about the link between epigenetic modifications and disease.
Tags: video, DNA, gene expression, epigenetics
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