1. ESTs Ian Keller Laboratory Techniques in Molecular Bio

3. Discovery Which scientists first used this method is unclear. Applied by many scientists in the early 1970s Also essential in the Human Genome Project

4. Expressed Sequence Tags Short, sometimes low quality segments of cDNA Usually approx. 100-800 bp in length Give useful information about expressed genetic material Particularly useful in identifying genes in eukaryotes Can be separated into 5’ and 3’ ESTs

5. Necessity Mapping genomes in prokaryotes is relatively simple Mapping genomes in eukaryotes is not Short-cuts are necessary to obtain useful information within vast amounts of non-useful information

6. Generation of ESTs mRNA isolated from target cells RNA cannot be cloned Complementary DNA must be made via reverse transcription Specialized enzyme, reverse transcriptase, is needed to do so

8. Databases dbEST

9. Limitations Can be very difficult to isolate mRNA from certain cell types Little indication which gene the EST is derived from Important genetic information may be contained within introns