h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

Entry: How To Extract Your Own DNA - A25442354
Author: Matt the Hoopy - U168592

This is a Flea Market Rescue

Original Entry here: A12857682

Original author contacted and credited

Enjoy.

Oh, it DOES work, I've tried it

Excellent I'm no biologist, but that looks like a great experiment. How do you do it with blood? Do you just hold the victim over the glass or what?

Enjoyable entry

We do this as an experiment at school, although not with saliva. The best results, for some reason, are from kiwi fruit.

B

Thanks,

The problem with blood is coagulation, and semen, well - ick!

Kiwi fruit? Fancy that. I've seen it done with peas and broccoli before.

Onions give good results as well

Al, I'll add them

Any more ideas for this, or is everyone happy?

It may be worthwhile stating that this is an adaptation of the Marmur process, used in many laboratories throughout the world.
May be an idea to give an overview of the whole process:

*Break up tissue mechanicaaly
*Detergent helps to degrade both the cell membranes and those surrounding the nuclei
* (In more complex operations, egg, involving plant tissues, cell fragments are removed by filtarion through e.g. coffee filter paper).
*(Proteins associated with the DNA can be removed by treating with a proteolytic enzyme).

The alcohol should be ice-cold. I can't remember what vessel you were using but, if you were using a boiling tube, one would pour it slowly down the side of the boiling tube.. Leave it 2 - 3 minutes without distrubing.

(DNA is insoluble in cold alcohol. Bubbles will be observed and, while other compoiunds in the mixture dissolve, the DNA will precipitate out)

When your extracting the DNA starnd, take care not to disturb the two layers too much , or to brek up the DNA strand - which is fragile.

Further Activities:

It might be possible to stain the DNA before examining under microscope.(There is an 'Usborne Book of Microscopy' which may have ideas for stains obtainable in the home).

The acidic nature of the DNA may be examined using Universal Indicator (I've never tried home-made indicators such as 'cabbage' - but this might be worth looking at (s to find out

Thanks for those Al, I'll do some hunting down of some more facts to beef it out a bit more

If you find me stuff about home indicators, I'll add it in

You're already credited to the Entry, what would I do without your chemistry knowledge eh?

'You're already credited to the Entry'

Yes, I justy notriced that about half-an-hour ago, and wondered ho long I'd been there


Here is an Entry which talks about cabbage indicator: A3403928


...and one which mentions beetroot indicator: A11454491

(Wonders whether it's worth writing an Entry which gives a coherent account of preparation, substances to test, expected results etc....

I think you're better off doing such an Entry for a couple of reasons;

1. You have the knowledge base!

2. I want to keep this one fairly simple and understandable so it can be done by anyone

Hello Matt, pleased to see beetroot mentioned without anybody shuddering!

<>
I think that should be:
If you're under the legal drinking age, you best ask permission to obtain said alcohol for this experiment.

Footnote one includes the punctuation within the link, and it shouldn't

Very interesting, although when I saw the title I thought it would be some bloke talking about their favourite pastime

It always comes down to doing it off the cuff doesn't it?

Sorted out those nitpicks.

'I think you're better off doing such an Entry for a couple of reasons;...'

Yeah I didn't mean to incorporate it in this one. I just meant that you could:

Write a couple of ideas for further work (As I outlined above), and

link to 'The Colour Blue' and 'Beetroot' Entries as ideas on how to test for acidic nature of DNA.


What I meant in my earlier posting is, perhaps it'd be worth MY while in writing a coherent Entry on extracting and testing acid-base indicators from plant material, which would pull together the cabbage and beetroot indicator Entries, and add a few more ideas.

A

Sounds like a plan to me sir!

I've added the acidity test to the Entry

Looking good Matt,

I think that under 'Method' I would still like to see an overview of what one is hoping to achieve, ie:


During this process it is necessary to break up tissue (in this case, cheek cells) mechanically and then to degrade both the cell membranes and those surrounding the nuclei. This is achieve by mechanical agitation in the presence of detergent.

When starting with more complex tissues, eg plant material, it is useful to remove cell fragments by filtarion through e.g. coffee filter paper).

In a refinement to the process, one can remove the proteins associated with the DNA by treating with a proteolytic enzyme A3328355.

<> *shudders*

PS I've been looking for my 'Usborne Book of Microscopy' to see what it says about stains available in the home, but I can't find it anywhere

<<<> *shudders*>>



lurkers!