4 replies to this topic

[galileo]

Hi,

I isolate DNA from white animal hair (with NaOH and HCl+Tris) and it works well. But It doesnt work with dark hair and I need to understand why. Could anybody help me? Is pigment in dark hair the reason or what?  Thank u.

[bob1]

The DNA is not actually in the hair, it should be in the root of the hair which is actively growing tissue, so the colour of the hair should not matter.  Having said that, pigments can interfere with DNA and RNA extractions, though I have never heard of melanin being a problem.

[Maddie]

Well, actually there is DNA in hair: mitochondrial DNA. And yes your problem is due to the melanin content. You need to clean up your extract.

see
Leopold Eckhart,* Ju¨ rgen Bach,* Jozef Ban,*,† and Erwin Tschachler*,‡,1
Melanin Binds Reversibly to Thermostable DNA
Polymerase and Inhibits Its Activity
Biochemical and Biophysical Research Communications 271, 726–730 (2000)

Edited by Maddie, 24 May 2010 - 12:52 PM.

[jamessmith01]

Well you learn something every day! How much hair do you need to get DNA, then?

[Maddie]

Very little if the hair is still "fresh". How do you think the police catches bad guy?  
It's very hard not to lose any hair on a crime scene, especially if there is a fight.

When the hair is old, then it gets more difficult and you'll need several cm.