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DNA cloning. General strategies Choose DNA sources (gDNA/cDNA) Produce collection of DNA fragments Join them to appropriate vector Introduce rDNA to a host cell Screen/Select transformants. Host Organisms. rDNA recipients Bacteria Yeast Mould Animal cell Plant cell.
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DNA cloning General strategies Choose DNA sources (gDNA/cDNA) Produce collection of DNA fragments Join them to appropriate vector Introduce rDNA to a host cell Screen/Select transformants
Host Organisms rDNA recipients Bacteria Yeast Mould Animal cell Plant cell
Transformation Plasmid Calcium chloride Heat shock Electroporation Phage/Cosmid/YAC Infection
DNA library Collection of cloned DNA sequences in host cells Require complete or near complete representatives of genome
DNA library Large DNA fragments Fewer number of clones Library of genome with 3 * 109 bp Inserts of 20 kb long Require 1.5 * 105 recombinant molecules
Types of DNA library Genomic Library representing the entire genome cDNA Library representing onlyexpressed genome
gDNA library construction Partial digestion of genomic DNA Ligation of fragments to vector of choice: plasmid, phage, cosmid, BAC or YAC
cDNA library construction Isolation of poly (A) RNA
cDNA library construction cDNA preparation
Library storage Homogeneous aliquots Deep freeze at -70 / -80 Celcius 20 % glycerol 7% DMSO
Library screening Southern/Western hybridization using specific probe Chromosome walking Differential hybridization Subtractive hybridization
Differential hybridization Individual colonies Microarray Library screening
DDRT-PCR Differential Display Reverse transcription (ase) Polymerase Chain Reaction Screening of differentially expressed genes Without library
DDRT-PCR Subsets of mRNA to be amplified Using 3’ oligo d(T) + dinucleotide primers 5’ arbitrary primers Size fractionation with PAGE Identification of polymorphic bands Sequencing and Expression verification
Genomic / cDNA clone Identification: Genome organization (gene/nongene) Gene structure (exon/intron) Regulatory regions/sequences Induction of mutation for functional analysis Identification: Differentially expressed genes Expression profiles