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Hair and DNA

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Hair and DNA

Postby Edher » Tue Dec 27, 2005 8:31 pm

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,
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Postby MrMistery » Tue Dec 27, 2005 9:22 pm

Yes, i believe the bottom of the hair folicule is made out of living cells. That is why hair grows
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Postby Enzyme » Wed Dec 28, 2005 5:28 pm

¡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).
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Postby tsunadeobaachan1791 » Wed Jan 04, 2006 2:30 am

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.
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Postby Ultrashogun » Wed Jan 04, 2006 6:08 am

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.
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Postby MrMistery » Wed Jan 04, 2006 8:23 pm

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
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Postby sdekivit » Wed Jan 04, 2006 8:49 pm

MrMistery wrote: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 :D
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Postby MrMistery » Wed Jan 04, 2006 10:06 pm

No idea... Do you know? Please share...
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Postby sdekivit » Thu Jan 05, 2006 10:19 am

MrMistery wrote:No idea... Do you know? Please share...


Yeah, i know :D

--> 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.
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Postby MrMistery » Fri Jan 06, 2006 7:46 pm

Thanks for the info. ;)
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Postby Dr.Stein » Tue Jan 17, 2006 4:12 am

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.
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Postby snoweq » Fri Mar 16, 2007 9:32 am

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
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