Final answer:
Genomic libraries contain all sequences of an organism's DNA, whereas cDNA libraries consist only of expressed gene sequences from mRNA, without non-coding regions and introns.
Step-by-step explanation:
The difference between genomic libraries and cDNA libraries lies in their origin and content. Genomic libraries are created by cloning random fragments of an organism's DNA into vectors, representing the entire genome, including non-coding regions like introns and regulatory sequences. In contrast, cDNA libraries are constructed from complementary DNA reverse transcribed from mRNA, representing only the expressed genes at a certain time, devoid of non-coding sequences and introns.
cDNA libraries are particularly useful for studying gene expression and protein coding because they contain sequences that directly correlate with the proteins produced by the cells. They provide an efficient way to study the active portion of the genome. Genomic libraries, however, are comprehensive and allow for the study of genetic material in its entirety.
A genomic library consists of fragments of an organism's genomic DNA, while a cDNA library consists of complementary DNA (cDNA) generated from the organism's messenger RNA (mRNA). The genomic library contains DNA from all genes in the organism, including non-coding regions, whereas the cDNA library only contains DNA from expressed genes.