AAT Bioquest

What are the differences between cDNA and genomic DNA library?

Posted March 1, 2023


Basis of differentiation 

cDNA library

Genomic DNA library


Is a collection of only the genes that are encoded by an organism

Is a collection of the complete genomic DNA of an organism


Contains only genes expressed in a particular cell at a given period of time

Contains all of the cell’s genes, whether expressed or not

Coding vs noncoding sequences

Contains only coding sequences – does not contain introns

Contains entire sequences for introns and exons


Smaller than genomic DNA library

Larger than cDNA library

Starting material



Ingredients essential for construction 

Reverse transcription enzyme

Ligases and restriction endonucleases

Involvement of reverse transcription

Reverse transcription is involved in the synthesis of the first cDNA strand 

Reverse transcription is not involved

Number of recombinants to be screened

Fewer than genomic DNA library

Larger number than cDNA library

Vectors used 

Plasmids, lambda phage, and phagemids are used for harboring smaller fragments as introns are absent

Lambda phage, cosmids, YAC, and plasmids are used to harbor larger fragments

Additional resources

Sequencing and comparative genomic analysis of 1227 Felis catus cDNA sequences enriched for developmental, clinical and nutritional phenotypes

DNA and RNA Quantitation

ReadiScript™ RT Reverse Transcription Kit