Friday, July 18, 2008


With so much talk of DNA, blowing in our bolehland, I was wondering whether most us (layman) know what exactly it is, or only a vague idea. Here I did some googling and came up with some explanation. Please read it if it is of interest to you (10 mins read)…..cheers.

What exactly is a DNA fingerprint? Well, it certainly isn't an inky impression of a DNA strand. Compared to unimaginably small DNA, a fingerprint is HUGE. So what is it that we're looking at, and how is one of these fingerprints made?

DNA. It's what makes you unique. It's the stuff that tells each and every one of your body's 10 trillion cells what it's supposed to be and what it's supposed to do. And although your DNA is different from that of every other person in the world -- unless you have an identical twin -- it's the same in every cell that makes up your body.

That DNA is unique from person to person but the same from cell to cell in one person can be a handy thing, especially when it comes to DNA fingerprinting. DNA fingerprints can be used for anything from determining a biological mother or father to identifying the suspect of a crime.

The best way to understand how DNA is used to solve a crime, is to play detective. So if your game, lets start.

The crime:

On the evening of November 1, at approximately 8:15 p.m., Raja Lolipo entered his bedroom, walked over to his desk, and sat down at his computer. While reaching for the computer's switch he noticed, out of the corner of his eye, that one of the items on a typically well-organized shelf was out of place.

Raja Lolipo shot across the room for a closer examination. Sure enough, the object in question had indeed been disturbed.

The object had been sealed in an air-tight package. The package was now ripped open. The object was still inside, but it was no longer in its original condition. In Raja Lolipo 's eyes, it was now worthless.

Raja Lolipo pulled out what had been his most-valued possession -- his holographic lollipop. The confectionery treat was now a sticky mess. Someone had obviously indulged him- or herself in its sugary molecules. The lollipop's holographic image had been licked away.

The suspects:

The prime suspects in this case are Raja Lolipo 's seven sisters: Candy, Cookie, Sugar, Lolly, Honey, Brandee, and Carmela. Each one of these sisters is a notorious candy lover and is easily capable of committing this crime of confection.

The suspects have been detained. The saliva of the seven suspects are taken for a DNA sampling.

What we as the investigating detective need to do:

Fortunately for this case, a lollipop cannot be licked without leaving behind a bit of saliva.

Your task, as the investigator is to a appoint a Lab who is capable to finger print DNA, to create a DNA fingerprint from the saliva left on the lollipop. You must then use the fingerprint to single out the culprit of this crime.

Steps required to get the photo graphic image of the DNA.

1: the DNA samples from the suspects are first combined with an restriction enzyme agent.

2: then a special tray with electrodes is then taken and “agarose” gel is poured into the tray.

3: then the mixture in step 1 is poured into the special tray and the electrodes are activated for electrophoresis to begin.

4: after a certain amount time has lapsed, a special nylon membrane is placed on the mixture in the special tray.

5: another mixture called “probes” is added to the nylon membrane. I believe this agent stains the DNA seeping out of the special nylon membrane.

6: the next step is to place an X-ray film on the top of the nylon membrane.

7: the final step is to develop the X-ray film with the aid of a developer instrument. The DNA image is exposed on this film, and there you go, you have the images of the DNA strand on the X-ray film….just like you bone X-rays.

Now to catch the culprit:

Once all the seven suspects DNA has been photographed (x-ray image), the its just the simple task to compare the DNA on the lollipop to the DNA of the seven suspects.

Below I have the images of the DNA, see if you match and discover the culprit.

my bet is "Honey" was the culprit, what was you expert opinion?....cheers

thanks to nova online for this explanation.

No comments: