Library · Genetics
Gene
Make it clearer
A gene is a stretch of DNA that holds the instructions for making something useful: almost always a protein, and in other cases an RNA molecule whose work ends right there, without ever becoming a protein. It is a piece with a trade of its own, not just any portion of the molecule.
When we say a gene is expressed, it means the cell is drawing on those instructions at that moment. The gene can be present without anyone using it. That is why a liver cell and a skin cell, holding the very same complete manual, express different sets of genes, like two workshops consulting the same handbook but opening it to different pages. And that use is not fixed either: it changes with conditions.
In brief
A gene is a region of DNA that carries the information for making a functional molecule: either a protein or an RNA.
Most genes encode proteins; others encode RNA molecules whose functions do not involve making proteins.
Gene expression means putting the information in a gene to use. Different cell types express different sets of genes, and a cell's pattern of expression can also change with conditions.
Two cells can contain the same DNA yet behave differently because they do not use the same genes at the same time.
Sources (2)
- National Human Genome Research InstituteGene
- National Human Genome Research InstituteGene Expression
This page explains the topic in general terms; it does not tell anyone what treatment to follow.
Updated