Extracting DNA from a banana
Вставка
- Опубліковано 17 лис 2018
- Here we show how to extract DNA from a banana using household items and easy-to-find reagents.
PROTOCOL
You can download a 1-page protocol from eduversum.org/cvif/wp-content...
USING MORE REAGENTS
We deliberately use the minimum possible number of reagents, but you can add a few more for further accuracy. For example, you could add a pinch of salt right before adding the ethanol in step 7, to aid the precipitation of DNA (but as you can see here, it precipitates fine without). Similarly, you can add a few drops of pineapple juice to the filtered liquid or to the lysis solution, to eliminate some proteins. This is because pineapple has bromelain, an enzyme that breaks up proteins, so this would give us purer DNA. However, it would not look very different, so we decided to leave it out in this case in order to have a simpler protocol, and just mention that the DNA is not pure. Also, it would have the obvious problem of having a second fruit into the mix, with its own DNA. Alternatively, you could use contact-lens washing liquid, which also has proteases, but this introduces a black-box reagent that we would rather avoid.
DNA FROM OTHER FRUITS
You can also follow this protocol to extract DNA from tomatoes and strawberries. The problem with tomatoes is that they have a lot of pigments (chiefly lycopene) that often stain the DNA, which should be colourless. Try with your local fruit and tell us in the comments how it went!
YOUR OWN DNA FROM SALIVA!
Extracting your own DNA from saliva is surprisingly easy:
1. Wash your mouth well using only water.
2. Gently rub the inside of your cheeks and lips against your gums, teeth and palate, to dislodge some cells (saliva itself has no DNA).
3. Spit some saliva directly into a test tube or vial (about 1 or 2 cm or 1/2 inch in height will do).
4. Add a couple of drops of washing up liquid.
5. Mix very well.
6. Add the alcohol just as we did in step 7.
REFERENCES
• Extract DNA from a ban... | bit.ly/2AJmwqI
RESEARCH
Victor Sojo & Aishwaria Lohi.
VIDEO
Victor Sojo & Janina Roemer.
Developed at Aavishkaar: Centre for Excellence in Maths and Science (aavishkaar-palampur.org), in collaboration with Science Corps (science-corps.org) and Eduversum (eduversum.org)
SUBTITLE TRANSLATIONS
Hindi: Apoorwa.
Castillian (Spanish): Victor Sojo.
German: Janina Roemer.
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I have watched a few videos of this particular experiment and so far yours is the best and most concise explanation of why you use Ethanol, detergent and water to extra DNA - Thanks!
This is definitely the best video on DNA extraction:)
Best "tutorial" so far, thanks a lot, appreciate it...keep it up !
Will it be ok if we dont chill the isopropyl alcohol?
Hello i have an inquiry! If the banana is chilled will it yield more DNA compared to the room temperature banana?
awesome presentation!!! may i ask how long it takes for the DNA to appear within the alcohol solution? thank you very much! :)
Withing 7 or 8 minutes
It can begin to happen immediately, but normally it will be a few minutes. Note that it is by no means pure DNA; in fact, it has a lot of protein, but there should also be plenty of DNA there.
awesome!
❤
Thank you for the video! Some other tutorials stress that the ethanol needs to be as cold as possible for the experiment to work - you did not. In the setting I would like to conduct this experiment it would be a little bit of a hassle to maintain low temperature. How necessary is it for the experiment to work? Best regards! :-)
Apologies for the late reply. When doing a precipitation by change/addition of a new solvent, temperature tends to be very important. This is typically-but not always-because higher temperatures tend to increase solubility whereas lower temperatures tend to decrease it (again, there are some solutes for which it's the other way around, but they're the minority). You would therefore do such a precipitation in a way in which the solutes you want are most soluble in the solvent that you want them, and least soluble in the other one, and the same for the solutes you don't want, but with the solvents reversed. Temperature often helps a lot with that. In this particular case, though, the experiment works well enough at any room temperature we've tried it, because we're neither trying to get pure DNA (there are many things going into the alcohol other than DNA, such as proteins and RNA), nor are we expecting to get all of it (quite a bit of it is being left in the water). Most likely, having the alcohol at low temperature would increase the purity (because fewer things would dissolve in it, in the hope that enough DNA still does).
Examples of reagents here?
Good day! What factors/factor affecting enzymes that are present or tested here?
It's difficult to say just from this experiment, but there would definitely be plenty of DNA-associated proteins such as histones, polymerases and so on. But please note that we're not testing for any of them (or for DNA), we just assume that this white blob is at least in part DNA based on its known solubility.
Describe the dna that you have obtained in the experiment?
uhmm how would you describe the appearance of the extracted dna?
gooey? :D
There are some that add salt? Does it still work?
Yes, it still works. The DNA is not pure, it contains many other things, such as RNA and proteins. To get pure DNA, we would need to do several other steps and include several other reagents that are not trivial. We considered that salt would not cause enough of a difference in this case to justify adding it, since it would require explaining yet another reagent and set of chemical phenomena associated with it.
@@eduversum Out of curiosity without getting into too much detail, is the salt just helping with the breakdown of the banana releasing water trapped within the flesh (like it does when added to meat before cooking) or is there more going on specifically with the proteins, fats RNA and DNA - like will it get a potentially more "pure" DNA sample?
Can I use sanitizer in place of alcohol
Please answer I want to do my experiment
Hi Shikha. We haven't tried with hand sanitizer. It probably depends on the fluidity of the sanitizer. If it is very viscous (a gel), then probably it would not work or would work very slowly, but if it is very fluid, then this should work. We have tried commercial liquors (e.g. vodka, rum, gin, all at around 40% v/v), and they all work somewhat at least. Of course, this may not be appropriate for use with and by children.
I think we can use methylated spirit as alternative of alcohol..
@@shikhasingh5043 We Can Also Use Nailpaint Remover instead of Alcohol...
You can Watch my Video I've done the same!😊
How to get pure DNA from this?
Very good question. There are many sources of contamination in this extraction procedure (which we meant only for demonstrative purposes in a non-professional laboratory). For example, there is the soap, some of which may make it into the alcohol portion. But most important of all are the proteins that are typically bound to DNA, such as histones. These are very difficult to remove with household items. One idea would be to use pineapple, which contains a molecule called bromelain; this is a protein (specifically an enzyme) that degrades other proteins, so we could use it to remove many of the proteins that are bound to the DNA. The problem of course is that now you would also have pineapple DNA mixed with the banana DNA.
So, if you actually want to purify this DNA, your best bet would probablly be to use one of the commercial kits that are specifically designed to extract DNA from plants.
Hey i want to present this experiment in the science model competition to be held at my school. I have one query : will it work if the pure/ 70% Isopropyl alcohol is not chilled? Can you please reply my asap.
Hello, as I myself as a student showed this experiment in my school, it is better to use chilled 70% isopropyl alcohol in order for more DNA to be extracted otherwise you may not get desired results.
So you can ask your school staff to keep your ethanol chilled in the refrigerator if not you could keep the small bottle of the alcohol wrapped in water and kept in your refrigerator at home and while going to school just take it with you in a polythene bag filled with ice.
Hope this helps, and good luck with your competition.😄👩🔬👨🔬
U didn't add salt
No. We were trying to keep the number of materials and reagents to a minimum, so that there would be as few things as possible that could cause confusion.
We can use 100 percent of ethanol
Yes, higher ethanol will work if you have it. 100% is extremely rare, though.
@@eduversum drinking alcohol will not work because that's only 15%
Where to get 70%?100%?
What percentage is hand sanitizer?
I know?????