Short sequences of DNA in the human genome that can be used to identify genes that are expressed as RNA are termed

Short sequences obtained by sequencing of cDNA clones from any cDNA library are termed expressed sequence tags (ESTs). One methodology in Human Genome Project is based on identifying all the genes that are expressed as RNA (ESTs). ESTs can be used to identify a gene that is being expressed in a cell at a particular time.

The other methodology took the blind approach of simply sequencing the whole set of genome that contained all the coding and non-coding sequence, and later assigning different regions in the sequence with functions (Sequence Annotation).