Library Amplification
Library Amplification - Related Videos
09:44
Rapid Amplification of cDNA Ends
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2023
Source: Pablo Sanchez Bosch2, Sean Corcoran2 and Katja Brückner1,2,3 1Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research 2Department of Cell and Tissue Biology, 3Cardiovascular Research Institute, University of California San Francisco, San Francisco, CA, USA Rapid Amplification of cDNA Ends (RACE) is a technique that allows amplification of full-length cDNA from mRNA by extending to the 3’ or 5’ end, even without prior knowledge of the sequence (Frohman et al.,...
11:14
Primer-Free Aptamer Selection Using A Random DNA Library
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Cited by 20 •
2010
SELEX protocols comprise multiple rounds of selection, each of which require regeneration of bound ligands, which in turn require fixed primer sequences flanking the random library regions. These fixed primer sequences can interfere with the selection process (false positives and negatives). Here we present a primer-free protocol.
09:12
MISSION LentiPlex Pooled shRNA Library Screening in Mammalian Cells
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Cited by 11 •
2011
Here we use a human LentiPlex pooled library and traditional sequencing methods to identify gene targets promoting cell survival. We demonstrate how to set up and deconvolute a LentiPlex screen and validate the results.
08:40
Genome-wide Screen for miRNA Targets Using the MISSION Target ID Library
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Cited by 1 •
2012
The Target ID Library is a plasmid-based, genome-wide collection of cloned cDNA used to identify miRNA targets. Here we demonstrate its use and application.
12:01
3' End Sequencing Library Preparation with A-seq2
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Cited by 9 •
2017
This protocol describes a method for mapping pre-mRNA 3' end processing sites.
FAQs
Adapter sequences create defined binding regions at the ends of prepared DNA fragments, while complementary primers recognize those regions during PCR. This arrangement directs copying toward adapter-ligated molecules rather than unmodified genomic fragments. It also allows correctly prepared library molecules to be enriched, supporting their subsequent detection in sequencing and other genetic assays.
Each PCR cycle increases the number of copies, but excessive cycling can cause some library molecules to become overrepresented relative to others. That amplification bias may distort the original fragment distribution and affect downstream genetic measurements. Selecting an appropriate cycle number helps produce sufficient material while better preserving library representation for variant discovery, genotyping, or genomic profiling.
The three PCR stages coordinate copying of adapter-ligated fragments. Denaturation separates DNA strands, annealing allows complementary primers to bind, and extension enables polymerase to synthesize new DNA. Repeating these stages creates additional copies of the targeted library molecules. Their coordination determines whether the reaction efficiently produces material suitable for downstream genetic analysis.
Cycle number and overall reaction conditions are central controls because they influence both the amount of product and how evenly different library fragments are represented. Poor control can favor some molecules over others, reducing correspondence with the original DNA library. Careful optimization therefore improves the reliability of sequencing-based variant discovery, genotyping, and genomic profiling.
The workflow begins with genomic DNA fragmentation, followed by modification of the resulting fragments with adapter sequences. The adapter-ligated material then undergoes PCR with complementary primers and repeated denaturation, annealing, and extension cycles. The amplified library provides enough DNA for sequencing or another downstream assay, while controlled cycling helps retain the original library’s representation.
It is useful when a prepared DNA library does not contain enough material for sequencing or other downstream assays. In genetics, the resulting amplified material can support next-generation sequencing, variant discovery, genotyping, and genomic profiling. Its value depends on maintaining representative fragment proportions, because amplification bias can influence the reliability of these downstream results.
Amplification can improve detection by generating sufficient copies of correctly prepared molecules, but uneven copying can alter the apparent representation of DNA fragments. Consequently, variant discovery, genotyping, and genomic profiling depend not only on obtaining enough product but also on controlling amplification conditions. Preserving the original library distribution makes downstream genetic results more reliable.