DNA sequencing - prep lab

Park walked me through the steps involved in the prep lab; this is my understanding of the process.
This small run was done manually, but large runs (the norm) are done on the robot machine that can process up to one hundred samples simultaneously.

The robot machine.

Park's notes of explanation.

The  samples were dissolved in a strong alkaline extraction solution and incubated at a high temperature to break down the cell walls  to allow for DNA extraction.  The yeast and bacteria samples, together with a positive and negative control, are incubated separately at different temperatures and cycles.  If it is not known if the sample is a bacteria or yeast, they are incubated in both, both usually scientists can tell by appearance.

The thermal cylinder used for incubating samples.

Tiny amounts of material are used, so the measurements have to be very exact. 

Some of the pipettes used to measure minute amounts.

The samples are pipetted into a BSA buffer solution which starts a polymer chain reaction to amplify the amount of DNA available for analysis.

 A loading dye, GelRed was added that has a heavier molecular weight than DNA allowing it to sink into the DNA.  Most chemicals used for DNA extraction comes form America or Germany, and are extremely expensive.
  
A process called Electrophoresis was run on this equipment.  DNA is negatively charged, so when a charge in run through the solution, each sample will make a distinct DNA ladder, which can be compared to others to help with  analysis.

Printout of the DNA ladders for my samples: bright bands denote bacteria;  lighter bands denote yeasts;  the two indistinct bands at either end are the negative and positive controls.

Samples are then placed in a air lock between the prep lab and the diagnostic lab to avoid contamination.