GENTECH archive


risks in alimentation : 4 questions


Some persons on the list (mainly from the "natural law party") have
claimed that (it is on their web site) :

>>Fragments of artificial genes inserted into foods were detected in the
>>brain cells of baby mice in research conducted Dr. Walter Doefler of the
>>Institute of Genetics, University of Cologne.(1)

And (1) seems to be :
Journal of molecular genetics and genetics Vol 242: 495-504, 1994.

I have been opposed that the comment on reference (1) is false
(see abstract in Medline at the end).

I would like those from the natural law party (others seem to be 
rigorous), either to stop giving
arguments that no one can check (was recently the case with Joe Toth),
or (even better) that they gave good references.

If they cannot give the good ones, I would like them to correct their

Am waiting for explanations.

Let me remind you that Jaan Suurkula <> wrote,
Thu Sep 10 11:34:27 1998:
>We have not yet been able to localize the study on brain cell uptake of
>viral DNA. 
Thanks to him for his honnesty.

Second question ;
The phage M13 has been detected even in the feces. I was answered that
the phage precisely has the possibility to insert into a genome.
I objected that it is irrelevant because the M13 has not been integrated.
apparently becaus it had been inactivated (as said Rick).
So it is only the fact that it is a sequence of bp that is relevant
and not its function.

Am I Right ?

third question : The phage is a whole (length ?). So, its
integration should be more likely than the integration of a gene
of a GMO (even if GMO are less stable than mutants one :
Nature 3 sep. 1998).
Am I right ?
Yet it seems not to have been integrated. Of course, it does not
prove that not ADN will ever be integrated, but these results are
very partial.

fourth question/comment : in the feces, up to 1692 bp have been detected
(only three expriments). It seems a lot. More than what had been
said on the list.

Is the epithelial lining of the mammalian gastrointestinal (GI) tract a 
tight barrier against the uptake of ingested foreign DNA or
can such foreign DNA penetrate into the organism? We approached this 
question by pipette-feeding circular or linearized
double-stranded phage M13 DNA to mice or by adding M13 DNA to the food of 
mice whose fecal excretions had previously
been shown to be devoid of this DNA. At various post-prandial times, the 
feces of the animals was tested for M13 DNA
sequences by Southern or dot blot hybridization or by the polymerase chain 
reaction (PCR). On Southern blot hybridization, the
majority of M13 DNA fragments were found in the size range between < 200 
and 400 bp (base pairs). For the PCR analysis,
synthetic oligodeoxyribonucleotide primers were spaced on the M13 DNA 
molecule such that the sizes of the persisting M13
DNA fragments could be determined. We also extracted DNA from whole blood 
or from sedimented blood cells of the animals
at different times after feeding M13 DNA and examined these DNA 
preparations for the presence of M13 DNA by dot blot
hybridization or by PCR. M13 DNA fragments were found between 1 and 7 h 
postprandially in the feces of mice. By PCR
analysis, fragments of 712, 976, and 1692 bp in length were detected. In 
DNA from blood, M13 DNA fragments of up to 472
bp were found by PCR between 2 and 6 h after feeding. Dot blot or Southern 
blot hybridization revealed M13 DNA at 2 and 4
h, but not at 1, 8 or 24 h after feeding. This DNA was shown to be DNase 
sensitive. M13 DNA was found both in blood cells
and in the serum. A segment of about 400 bp of the DNA amplified by PCR 
from feces or blood was analyzed for its
nucleotide sequence which was found to be identical to that of authentic 
M13 DNA, except for a few deviations. M13 DNA
could not be detected in the feces or in the blood of the animals prior to 
feeding or prior to 1 h and later than 7 h after feeding.
These controls attest to the validity of the results and also argue 
against the possibility that the murine GI tract had been
colonized by phage M13. Moreover, M13 DNA-positive bacterial colonies were 
never isolated from the feces of animals that had ingested M13 DNA.