PCR based methods . Reactions conditions *Target DNA ( or template) Reaction buffer containing the co-factor MgC *One or more primers *Thermostable DNA polymerase *Four nucleotides (dATP, dCTP, dGTP, dTTP)
1. Reactions conditions*Target DNA ( or template)*Reaction
buffer containing the co-factor MgCl2*One or more
primers*Thermostable DNA polymerase
2. Use of DNA polymerase= an enzyme that can synthesize DNA at
elevated temperature ex : Taq = enzyme purified from hot spring
bacterium : Thermus aquaticus3. Thermal cycle*Denaturing step - one
to several min at 94-96 C*Annealing step - one to several min at
50-65 C*Elongation step - one to several min at 72 C4.
Repetitiontypically 20 to 50 times average 35 times
4. SNPs (Single Nucleotide Polymorphisms)Any two unrelated
individuals differ by one base pair every 1,000 or so, referred to
as SNPs.Many SNPs have no effect on cell function and therefore can
be used as molecular markers.
DNA sequencing
Single gene trait: seed shapeMultigenic trait; ex: plant growth
=Quantitative Trait LociTypes of traits =types of markers
USES OF MOLECULAR MARKER Measure genetic diversityMapping
Tagging
