1. Lab # 1: Laboratory practices and Plant DNA extraction at home
Practical Of Genetics
BIOL 2121
Lab # 1: Laboratory practices and Plant DNA extraction at home
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2. Objectives:
To introduce the student the Laboratory practices and safety used.
To introduce the different micropipettes.
To introduce the concepts and calculations for dilutions and solutions.
Plant DNA extraction at home.
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3. 1- Some of the labs. Materials are dangerous:
All of the chemicals listed below are highly toxic and hazardous compounds. Take extreme care when handling these compounds. On contact with skin/eyes wash immediately with water:
Ethanol.
Methanol.
Acetic acid glacial.
Hydrochloric acid ( HCl ).
Ultraviolet Transilluminators.
Sodium hydroxide.
Ethidium Bromide.
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4. (Micro Pipette,Gilson) Pipetman
2- To introduce the different micropipettes:
               (Micro Pipette,Gilson) Pipetman
Model µl P2 µl
P10 µl
P20 µl
P100 µl
P200 µl
P1000 µl
P5000
1 -10 ml
P10ml
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6. Symbol
Name 
Factor d
deci
10-1 c
centi
10-2 m
milli
10-3
micro
10-6 n
nano
10-9 p
pico
10-12 f
femto
10-15 a
atto
10-18 z
zepto
10-21 y
yocto
10-24
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7. 3- To introduce the concepts and calculations for dilutions and solutions:
Preparing reagents and solutions is a never-ending task in most laboratories.
This is a basic laboratory skill that often confuses people at first.
Here we present the standard, general approach to computing dilutions and concentrations; the Dilution Factor Technique.
It is a convenient way of computing dilutions at the bench.
Work through this section BEFORE coming to lab.
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8. Terminology and Concepts:
Stock solution: concentrated solution which is being diluted
Working solution: diluted solution, ready to use.
Diluent: the fluid used for diluting concentrate.
Aliquot: a measured sub-volume of original sample.
Dilution factor (DF): ratio of final volume/aliquot volume
(final volume = aliquot + diluent)
Concentration factor (CF): ratio of aliquot volume divided by the final volume (inverse of the dilution factor)
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9. Example: What is the dilution factor if you add 0
Example: What is the dilution factor if you add 0.1 mL aliquot of a specimen to 9.9 mL of diluent?
The final volume is equal the the aliquot volume plus the diluent volume:  0.1 mL mL = 10 mL
The dilution factor is equal to the final volume divided by the aliquot volume: 10 mL/0.1 mL = 1:100 dilution (102)
The Concentration Factor for this problem = aliquot volume/final volume = 0.1/( ) = 0.01 or 10-2 concentration
This is sometimes given as:
C1 X V1 = C2 X V2
Remember:
V2 > V1
C2 < C1
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10. Concentrated stock solutions - using "X" units:
Stock solutions of stable compounds are routinely maintained in labs as more concentrated solutions that can be diluted to working strength when used in typical applications.
The usual working concentration is denoted as 1X. A solution 20 times more concentrated would be denoted as 20X and would require a 1:20 dilution to restore the typical working concentration.
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11. Molarity :
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12. 4- Plant DNA Extraction
Plant DNA Extraction at home: Strawberry fruit and Onion bulb:
Background: The long, thick fibers of DNA store the information for the functioning of the chemistry of life. DNA is present in every cell of plants and animals.
The DNA found in strawberry and onion cells for example can be extracted using common, everyday materials. We will use an extraction buffer containing salt, to break up protein chains that bind around the nucleic acids, and dish soap to dissolve the lipid (fat) part of the strawberry cell wall and nuclear membrane.
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13. Cont.
Alcohol is used to precipitate the DNA. Because DNA is soluble in water, alcohol (ethanol) causes the DNA to precipitate and come out of the solution.
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14. Materials heavy plastic bag. strawberry & Onion bulb.
DNA Extraction buffer (soapy, salty and water).
Cheesecloth and funnel.
50mL vial / test tube.
glass rod, inoculating loop, or popsicle stick.
Ethanol 90%.
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15. Cont. Extraction buffer: detergent (dishwasher or shampoo).
Detergent/salt solution:
20 ml detergent
20 g non-iodized salt
180 ml distilled water
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16. Procedure for Strawberry DNA extraction:
Place one strawberry in plastic bag.
Smash/grind up the strawberry using your fist and fingers for 2 minutes. Careful not to break the bag!
Add 10mL of extraction buffer (salt and soap solution) to the bag.
mush the strawberry in the bag again for 1 minute.
Assemble your filtration apparatus as shown bellow.
Pour the strawberry slurry into the filtration apparatus and let it drip directly into your test tube.
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17. Cont. Slowly pour cold ethanol into the tube. OBSERVE 5 minutes.
Dip the loop or glass rod into the tube where the strawberry extract and ethanol layers come into contact with each other. OBSERVE
extract a sample of DNA from the tube and place it on a clean  microscope slide; level the mass on the slide and stain it with a nuclear dye (ex: Toluidine, Methylene Blue, Aceto-Orcein; if necessary, add a little water and mount the coverslip.
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18. Image
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19. Good Luck
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