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From: larry@kitty.UUCP (Larry Lippman)
Newsgroups: sci.chem,sci.bio
Subject: Re: Blood and detecting "Pool P"
Summary: Unlikelihood of DNA sequencing from old, dried blood
Message-ID: <4200@kitty.UUCP>
Date: 26 Nov 90 03:36:48 GMT
References: <1990Nov10.021059.16136@morrow.stanford.edu> <1990Nov25.154239.17434@phri.nyu.edu>
Organization: Recognition Research Corp., Clarence, NY
Lines: 36

In article <1990Nov25.154239.17434@phri.nyu.edu>, roy@phri.nyu.edu (Roy Smith) writes:
> larry@kitty.UUCP (Larry Lippman) writes:
> > I feel confident that 300-year old blood can be reliably identified *as
> > blood*, I am highly doubtful that any species identification can be made.
> 
> 	Would it be possible to recover enough DNA to do PCR on it?

	I don't believe that any DNA fragments would exist in the dry
condition of a 300-year old blood stain, notwithstanding the fact that
mature mammalian erythrocytes don't have a nucleus, mitochondria,
ribosomes, etc.  Leucocytes are a true cell with a nucleus and DNA,
but I rather doubt that any would be found in a 300-year old blood
stain.

	I can't offer any authoritative comments on DNA issues, though.
I don't do DNA, genetic mapping or any aspect of molecular biology.
I have enough trouble maintaining competency in selected more traditional
aspects of chemistry and biochemistry! :-)

> Actually, it just occurred to me that red blood cells don't have DNA, if I
> remember correctly, but maybe some other component of blood does?

	As far as I can recall, no *mature* mammalian erythrocytes possess
DNA.  Erythrocytes of birds, reptiles, etc. do have a nucleus with DNA and
all the trimmings, though.

> 	Now, about "Pool P", everybody knows that the way to detect it is
> to look for the warm spots. :-)

	That's the solution!  An IR thermographic imaging system coupled
with a VCR to catch the perpetrator in the act!  Showing instant replays
would probably be more embarrassing than any chemical indicator... :-)

Larry Lippman @ Recognition Research Corp.  "Have you hugged your cat today?"
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