Genetically Modified Food Animals Coming

[Guest guest]

press-release

Genetically Modified Food Animals Coming

Mon, 25 Sep 2006 18:47:39 +0100 (BST)

 

 

 

 

 

The Institute of Science in Society Science Society

Sustainability http://www.i-sis.org.uk This article can be

found on the I-SIS website at http://www.i-sis.org.uk/

 

 

========================================================

 

ISIS Press Release 25/09/06

 

Genetically Modified Food Animals Coming

********************************************

 

 

Foods derived from genetically modified animals are far from

safe. They are likely to be contaminated by potent vaccines,

immune regulators, and growth hormones, as well as nucleic

acids, viruses, and bacteria that have the potential to

create pathogens and to trigger cancer.

 

Prof. Joe Cummins and Dr. Mae-Wan Ho

 

The Codex Alimentarius Commission of the United Nations is

preparing guidelines for safety assessment of foods derived

from recombinant-DNA animals [1]. Comments on the topic can

be submitted before 1 October 2006 to Codex Alimentarius

Commission FAO Viale delle Terme di Caracalla 00100 Rome,

Italy, Fax: +39 06 5705 4593 E-mail: codex Copy

to:Dr. FUJII Mitsuru Counsellor, Minister's Secretariat,

Ministry of Health, Labour and Welfare 1-2-2 Kasumigaseki,

Chiyoda-ku 100-8916 Tokyo, Japan Fax: +81 3 3503 7965 E-

mail: codexj . It is likely that the

establishment of food safety assessment guidelines will be

followed by an avalanche of applications for releasing

genetically modified (GM) animals.

 

Codex distinguishes between heritable and non-heritable

genetic modification of food animals. Heritable genetic

modification involves genetic changes that persist in sperm

and egg while non-heritable modification involves the

introduction of modified genes such as vaccines into the

somatic tissue of animals. Codex asks: " Are there specific

food safety questions (e.g. with regard to types of vectors)

that should be considered relative to the assessment of

safety of food from animals containing heritable versus non-

heritable traits? "

 

Our submission for the Institute of Science in Society

provides a review of both heritable and non-heritable

genetic modifications of animals for food, followed by

specific comments.

 

A. Heritable Modifications of Food Animals

----------

 

Heritable alteration or genetic modification (GM) of food

animals has been achieved since the early 1980s, mostly by

injecting naked DNA. Between 1 and 20 million copies of the

transgene (gene to be integrated into the animal genome) are

injected into the embryo pronucleus (the nucleus before

fertilization) or into the egg cytoplasm, with at most about

one percent of injected embryos becoming transgenic animals.

The transgenes integrate randomly, though rare instances of

homologous recombination with host genes may occur.

 

A number of different vectors have been used to deliver

transgenes. Transposons (mobile genetic units capable of

transferring genes) are not widely used in vertebrates.

Lentivirus (lenti-, Latin for " slow " ), a genus of slow

viruses of the Retroviridae family characterized by a long

incubation period, can deliver a significant amount of

genetic information into the DNA of the host cell, and are

among the most efficient gene delivery vectors. HIV (human

immunodeficiency virus), SIV (simian immunodeficiency

virus), and FIV (feline immunodeficiency virus) are all

examples of lentiviruses that have been used successfully

with farm animals such as chicken, pig and cow. They are

about 50 times more efficient than DNA injection at

producing transgenic animals. One problem encountered is

that the long terminal repeats of the integration vector

interfere with the inserted gene's promoter. Homologous

recombination has been used to produce specific gene " knock

outs " by replacing an active gene with an inactive one.

" Knock in " refers to the integration of a foreign gene at a

specific target, disrupting the target gene by inserting the

transgene.

 

Transgenes are designed according to rules that result in

gene expression in the host animal, such as the presence of

at least one intron, exclusion of GC rich regions,

particularly CpG rich motifs. Gene sequences called

insulators are often included; these contain transcription

enhancers and enhancer blockers to avoid cross talk with

adjacent genes, and chromosome openers that modify histones

to allow the transcription machinery to be expressed.

Finally, RNAi may be used to inactivate specific genes

either as heritable transgenes or as non-heritable gene

treatments [2]. A lentivirus vector based on HIV

dramatically increased the efficiency of producing

transgenic animals, thereby greatly reducing cost. Foetal

fibroblast cells can be modified and then cloned to produce

transgenic animals [3].

 

Read the rest of this article here

 

http://www.i-sis.org.uk/Genetically_Modified_Food_Animals_Coming.php

 

========================================================

This article can be found on the I-SIS website at

http://www.i-sis.org.uk/

 

If you like this original article from the Institute of

Science in Society, and would like to continue receiving

articles of this calibre, please consider making a donation

or purchase on our website

 

http://www.i-sis.org.uk/donations.

 

ISIS is an independent, not-for-profit organisation

dedicated to providing critical public information on

cutting edge science, and to promoting social accountability

and ecological sustainability in science.

 

========================================================

CONTACT DETAILS

 

The Institute of Science in Society, PO Box 51885, London

NW2 9DH

 

telephone: [44 20 8452 2729] [44 20 7272 5636]

 

Foe email details, see http://www.i-sis.org.uk/contact.php

 

MATERIAL ON THIS SITE MAY NOT BE REPRODUCED IN ANY FORM

WITHOUT EXPLICIT PERMISSION. FOR PERMISSION, PLEASE CONTACT

ISIS at http://www.i-sis.org.uk/contact2.php