Transcript DNA LIBRARIES

DNA LIBRARIES
Dr. E
What Are DNA Libraries?
• A DNA library is a collection of DNA fragments
that have been cloned into a plasmid and the
plasmid is transformed into a bacteria for
propagation and storage.
• Ideally contains at least one copy of every
sequence.
• Allows researchers to identify and isolate the
DNA fragments that interest them for further
study.
What Are The Two Types
Of Libraries?
• Genomic library-A set of cloned DNA
fragments that collectively represent the
entire genome of a given organism.
• cDNA library-represents a sample of all the
expressed mRNA’s from a particular cell type,
particular tissue, or an entire organism which
has been converted back to DNA. Thus
represents the genes that were actively being
transcribed (turned on).
Applications Of cDNA
Libraries
• Discovery of novel genes
• Determine what mRNA’s are expressed in
different cells or tissues
• Determine what mRNA’s are expressed at
different developmental stages
• Study alternative splicing
Applications Of Genomic
Libraries
• Determine the complete genome sequence
• Study of regulatory sequences
• Study promoters
• Study intergenic regions
• Study Introns
• Study non-expressed gened
Making a Genomic
Library
Making a cDNA Library
Separating mRNA
Creating cDNA
Inserting cDNA Fragment
into Plasmid
Where is cDNA Fragment
Inserted into Plasmid?
pTriplEx Plasmid
Anatomy Of A Gene