# data[].attributes.body
Iris: iride
Double strand: doppio filamento
Dandruff: forfora
Sample: campione
RFLP: restriction fragment length polymorphism
Frictional force: forza d'attrito
To repel: respingere
Rate of migration: velocità
Stain: colorante
Bite impression: il morso
Auricle shape: forma delle orecchie
Palindromic sequence: sequenza palindromica
Finger-print: impronta digitale

# data[].attributes.attachment_link.description
TOUCH this image to discover its story. Image tagging powered by ThingLink

# data[].attributes.attachment_link.description
TOUCH this image to discover its story. Image tagging powered by ThingLink

# data[].attributes.attachment_link.title
Positive Pole, Negative Pole, Wells, Making an Agarose Ge... by Alice

# data[].attributes.attachment_link.description
TOUCH this image to discover its story. Image tagging powered by ThingLink

# data[].attributes.headline
What role does DNA evidence play in solving crimes?

# data[].attributes.subject
What role does DNA evidence play in solving crimes?

# data[].attributes.body
Why has DNA received a  lot of media attention?
DNA has received a lot of media attention because it has a fantastic power of discrimination.

How long has DNA  been used to identify people?
DNA has been used to identify people since the mid 80s, but now technologies are more developed.
The techniques used nowadays are more sensitive. How much DNA is needed to do a test?
To do a test it's needed less than a gram of DNA.

How many cells are needed to get a full profile?
To get a full profile three or four cells are needed.

In what conditions must the exhibit be kept?
The exhibit must be kept dry or frozen.

How long does DNA last if taken in good conditions?
DNA taken in good conditions will last essentially forever.

# data[].attributes.body
Ho caricato il pdf perchè il PowerPoint è troppo pesante.

# data[].attributes.body
At the beginning, read the list and  individually select the three items you think influence more electrophoresis result.
My group (Bergamini, Scainelli and me) selected these four items : presence of Mg ions; buffer solution pH; agarose gel concentration and presence of bubbles in the gel.
Later on you will discuss your choises in pairs you should find an agreement on three items, some of them must be "trade off" and you must find compromises.
We compared our decisions with another group (Bretta and Brina) and we discussed about our choices. They chose: voltage applied to the electrophoretic cell; presence of Mg ions; buffer solution pH. Finally togheter we decided what items were important.
In group of four you should discuss once more the best three items of each group.
At the end of the discussion we decided: presence of Mg ions; buffer solution pH; agarose gel concentration.
Class discussion on results.
The three most important items are: voltage applied to the electrophoretic cell because we need the right voltage to avoid destroying the gel; buffer solution pH because the DNA has to be negatively charged; agarose gel concentration because agarose gel is a molecular sieve that depends on the concentration of agarose (for small fragments we need an high concentration); presence of bubbles in the gel because if there are bubbles DNA won't run correctely.

# data[].attributes.headline
DNA from the crime scene and suspects (2)

# data[].attributes.subject
DNA from the crime scene and suspects (2)

# data[].attributes.body
What is the basic principle of gel electrophoresis?
The basic principle of gel electrophoresis, that is agarose gel, it's that it is a molecular sieve.

Why does DNA migrate toward positive electrode?
DNA migrates toward positive electrode at pH 8.0 it's negatively charged.
What is the TBE composition?
The TBE composition is: NaCl, Tris-HCl and Mg²⁺ ions.

Why is important to add Mg ions? Are they co-enzymes or cofactors?
It's important to add Mg ions because they favor the digestion of DNA. They are cofactors.

How can DNA be detected in agarose gel?
DNA can be detected in agarose gel by using an intercalant dye and putting it under UV linght (transilluminator).
Why are DNA dyes dangerous for human health?
DNA dyes are dangerous for human health because they contain mutagenics substances, dangerous for our DNA.

What should be done to prepare an agarose gel?
To prepare an agaorose gel we should: put agarose powder in a conic flask; add 10mL of TAE; put the conic flask in a microwave owen until the solution is completely transparent; pour the solution in the gel tray and create wells by using a comb.

What should not be done preparing an agarose gel?
When we are preparing an agarose gel we shouldn't done: pour quickly the solution in the gel tray; don't leave bubbles in the gel; don't leave the conic flask inside the microwave without checking it.
Which piece of information can be find out from a DNA pattern bands?
From DNA pattern bands we can discover who is the culprit of a crime.

# data[].attributes.body
Was it possible to identify people in the past? How?
Yes, in the past it was possible to identify people by the eyes color, finger-print, jewels, bite impression. Human identification has been historically based on finger-printing since 1901.
When was used first DNA finger printing?
DNA finger printing was used for the first time in 1988 to solve a case of rape and murder.
Where can DNA be obtained from?
DNA can be obtained from blood (only white cells), semen, hair with roots, skin, dandruff, sweat stains, urine, feces, vaginal fluids, liquid in contact of mucosa, nasal secretion.
Who invented RFLP technique? When?
RFLP technique was inveted by Alcec J. Jeffrey, molecular geneticist at the University of Leicester UK, in 1984.

What is a restriction enzyme?
Restriction enzyme is a protein that cuts DNA at particular base sequences.

What is restriction enzyme role in nature?
The role of the restriction enzyme inside bacteria is to protect  them against viral DNA infection.