Hair and DNA

[Edher]

Saludos,

Is it really possible to use hair for things such as paternity tests, identification of the culprit a crime scence, etc? As far as I'm concerned hair is composed of proteins not cells, how can they extract DNA from it? Is it perhaps from the part that was connected to the hair follicle?

Thank you,
Edher

[MrMistery]

Yes, i believe the bottom of the hair folicule is made out of living cells. That is why hair grows

[Enzyme]

¡Saludos Edher!

The hair folicule which is in the base of hair, contains live cells (therefore, these cells has DNA). For using it in analysis of DNA (paternity tests, crime investigations, etc), the hair must be uprooted. The hair which falls as breakage isn't usefull for these analysis (it doesn't contains DNA).

[tsunadeobaachan1791]

The hair follicle has a certain pattern within it, so they use that specific pattern that each person has to identify it. If they find that the patterns match, then then, it's hair from the same person.

[Ultrashogun]

Ahhh, I always asked myself this, because it shouldnt be possible to track back DNA from the aminoacid sequence of the hair, and the hair protein, I think its alpha keratin, isnt unique from person to person.

[MrMistery]

It's not possible. keratine has the same structure for every person. But the hair folicle contains live cells at it's root that do contain DNA. By PCR-ing this DNA we can find out the person's identity

[sdekivit]

It's not possible. keratine has the same structure for every person. But the hair folicle contains live cells at it's root that do contain DNA. By PCR-ing this DNA we can find out the person's identity

do you also know what DNA they are examining in a paternity test/crimes and so on ? coding DNA or non coding DNA

[MrMistery]

No idea... Do you know? Please share...

[sdekivit]

No idea... Do you know? Please share...

Yeah, i know

--> it's the non coding region of the DNA and they check for so called VNTR --> variable number of tandem repeats. These are repeats of a specific DNA-sequence that is repeated after each other

--> by taking 10 different VNTR you'll get a good identification method.

You can amplify the VNTR with PCR and than analyse on a gel, which yields to band pattern seen on television.

[MrMistery]

Thanks for the info.

[Dr.Stein]

Yeah, this is my question from time to time and I got the clue here though some words are still unfamiliar for me Thanks anyway.

[snoweq]

Can you please tell me if someone takes a lock of hair and it is over 5 years old and possibly does not have the follicles attached, is there anyway you can use this for DNA..I think I know the answer but replies would be good