TOOLS AND TECHNIQUES DNA Fingerprinting

Intoducing the microLiter! A TINY amount…a millionth of a Liter Very difficult to measure because it is SOOO small Incredibly accurate when measured correctly  Tools that measure these amounts are therefore INCREDIBLY expensive…be VERY careful with them!!! If a milliliter (mL) is 1/1000 of a Liter…  A microliter (μl) is 1/1000 of a millileter (mL)  The greek letter “mu” is used to represent micro (μ) Let’s PRACTICE  Work through the second page of the packet “DNA Fingerprinting – Practice Worksheet”

The TOOLS DNA Fingerprinting makes use of tools that can work with incredibly SMALL volumes  We only need a very small sample of DNA  We can run hundreds or thousands of samples at once in small spaces  We can be INCREDIBLY accurate and precise  We can use robotic assistance to run the full analysis

The Micropipette Are like a normal pipette…but better They can hold incredibly small amounts of liquid with incredibly high accuracy and precision  This makes them VERY expensive!!! Two types that we will use:  P20: Can hold up to 20 μl  P200: Can hold up to 200 μl

Draw and label a picture to refer back to:

Setting the Micropipette Each micropipette has a dial for its particular volume maximum  NEVER set the dial above the MAXIMUM listed, this will damage the micropipette  For a p20…NEVER set above 20 The three numbers represent the three place values  Starting with the largest POSSIBLE place value Let’s PRACTICE with the second half of practice worksheet

Techniques for Using Tips NEVER TILT THE PIPETTE!!! NEVER USE A NAKED PIPETTE!!!  We use tips to hold liquid, not the pipette itself  Liquids can actually damage (very severely) the internal parts To pick up a tip, push the pipette into the tip holder  ALWAYS keep the tip box COVERED  This keeps out contaminants After using ANY liquid, we will switch tips  This will also help minimize the risk of contamination through mixing of samples To eject a tip, push down on the SIDE button  This is attached to the metal rod that will push down on the tip  Always eject tips into a WASTE BIN

Techniques for using a Micropipette Push the PLUNGER to the FIRST Stop  DO NOT GO FURTHER THAN THE FIRST STOP  We must create a vacuum in order to pick up liquid While holding it down, insert the tip into your liquid  DO NOT LET GO UNTIL YOU ARE IN LIQUID  This will pick up air, not the liquid Release the plunger to pick up the liquid To eject, move the tip into the desired container  Hold the tip against the inside surface of the container you wish to eject into  Push the PLUNGER to the SECOND Stop to eject ALL liquid Let’s practice!  Get a pipette each and practice picking up and ejecting a tip, and pushing the plunger to the FIRST and SECOND stop

Using the microcentrifuge NEVER LOAD IT SIDEWAYS  Like a washing/drying machine, it will spin out of control and potentially break ALWAYS balance the load  In a 6-holder, this means you can load…  NOT One  Two  Three  Four  NOT Five  Six

Balance the epitubes in the rotor

Let’s practice!!! Do activity One and Two on the second instructional handout  Answer the first two questions by converting  Answer questions 3 and 4: the “Lab Observations” We will discuss and answer remaining questions after returning from break