1. A method of sequencing comprising: sequencing a plurality of cDNAs, wherein the cDNAs are obtained from a plurality of different sources, and: (a) each of the cDNAs comprises: (i) a tag that indicates from which source a cDNA is derived and (ii) separate from the tag, a binding site for a sequencing primer; (b) the sequencing is done using the sequencing primer; and (c) the cDNAs have been selected from a pooled cDNA sample; to obtain, for each of the sequenced cDNAs, the nucleotide sequence of the tag associated with the cDNA and the nucleotide sequence of at least a portion of a cDNA.
1. A method of sequencing comprising: sequencing a plurality of cDNAs, wherein the cDNAs are obtained from a plurality of different sources, and: (a) each of the cDNAs comprises: (i) a tag that indicates from which source a cDNA is derived and (ii) separate from the tag, a binding site for a sequencing primer; (b) the sequencing is done using the sequencing primer; and (c) the cDNAs have been selected from a pooled cDNA sample; to obtain, for each of the sequenced cDNAs, the nucleotide sequence of the tag associated with the cDNA and the nucleotide sequence of at least a portion of a cDNA. 7. The method of sequencing of claim 1 , wherein the method further comprises analyzing the sequences to identify a sequence variation.