The Transcriptome

Only a very small percentage (1.2% in humans) of the DNA in vertebrate genomes encodes proteins (the "proteome") because

So even when the complete sequence of a genome is known, it is often difficult to spot particular genes (open reading frames or ORFs).

One approach to solving the problem is to examine a transcriptome of the organism. Most commonly this is defined as: All the messenger RNA (mRNA) molecules transcribed from the genome.

Link to a discussion of gene transcription.

(Speaking strictly, one would define the transcriptome as all the RNA molecules — which includes a wide variety of untranslated, nonprotein-encoding RNA [Link to examples] — transcribed from the DNA of the genome. It is now thought that 76% of our DNA is transcribed into RNA although only 1.5% of this is messenger RNA for protein synthesis.)

It is "a" transcriptome, not "the" transcriptome, because what genes are transcribed in a cell depends on

Expressed Sequence Tags (ESTs)

ESTs are short (200–500 nucleotides) DNA sequences that can be used to identify a gene that is being expressed in a cell at a particular time.

The Procedure:

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26 September 2012