In genetics, an Expressed Sequence Tag (EST) is a short, identifiable piece of a longer DNA sequence. Specifically, an EST is a short sub-sequence of a cDNA sequence. ESTs are useful tools in gene research.
Uses of ESTs
ESTs serve multiple purposes:
- Gene Identification: ESTs can be used to find and identify gene transcripts. By matching an EST to a known gene sequence, scientists can determine if that gene is being expressed (active) in a particular cell or tissue.
- Gene Discovery: When an EST doesn't match any known gene, it can indicate the presence of a new, previously unidentified gene.
- Gene-Sequence Determination: ESTs contribute to determining the complete sequence of a gene. As short, known sequences, they provide anchor points for assembling larger sequences.
- Mapping: ESTs can be used to map genes to specific locations on chromosomes.
- Expression Studies: Examining which ESTs are present in a cell or tissue can reveal which genes are actively being expressed. This is helpful in understanding cellular function and development.
Key Characteristics of ESTs
| Feature | Description |
|---|---|
| Length | Short, typically a few hundred base pairs. |
| Origin | Derived from cDNA (complementary DNA), which is made from mRNA transcripts. |
| Utility | Used for gene identification, discovery, sequencing, and mapping. |
In summary, ESTs are valuable genetic tools for identifying and characterizing genes, enabling various biological research endeavors.
