Ch. 8: Recombinant DNA and Genetic Engineering

Terms in this set (65)

A library encompassing an entire genome.
Because the identity of a cloned DNA segment in which we are interested isn't known ahead of time, in order to make sure that we've cloned this segment, we make collections of DNA segments that are all-inclusive.
e.g., (1) take all the DNA from a genome, (2) break it into segments of the right size for the cloning vector we're using (collectively these segments represent the entire genome), (3) transform or transduce these molecules into separate bacterial recipient cells, where they're amplified. (**) We call the resulting collection of recombinant DNA-bearing bacteria or bacteriophages the genomic library*
Partly by chance and partly because some sequences from other genomes replicate less will in bacteria than do others, one genome's worth of clones would in reality contain multiple copies of some parts of the genome and no copies of other parts. To ensure that all sequences of the genome that can be cloned are contained within a collection, genomic libraries typically represent an average segment of the genome at least five times. This multifold representation makes it highly unlikely that, by chance, a sequence would not be represented at least once in the library.
This library has the benefit of containing genes in their native from, including introns and untranscribed regulatory sequences If the purpose of constructing the library is a prelude to cloning an entire gene or an entire genome, then a genomic library is necessary at some stage