ISIS Report 20/02/12
Unspinning the Web of Spider-Goat
Breeding transgenic goats for spider silk is unethical, and
passing surplus goats onto the public food chain unsafe; the project has never
been subject to regulatory risk assessment and there is not a single report
characterizing the transgenic sequences in the spider-goats’ genome Dr. Mae-Wan
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A concerted PR campaign
Within the past two years, a concerted media campaign has
been launched to promote the ‘spider-goat’, a goat genetically engineered to
produce spider silk proteins in its milk. Many of us were caught by surprise,
because transgenic animals and the associated somatic cell nuclear transfer
cloning began in the late 1990s  (Why Clone At All?, ISIS
report), and have been practically abandoned a decade later on account of the
low success rates on top of the unacceptably high rates of death and
abnormalities, and suffering inflicted on both cloned animals and surrogate
mothers (see  Unacceptable
Death Rates End Cloning Trials in New Zealand, SiS 50).
The current public relations
campaign started in May 2010 with a report and video presentation from the US
National Science Foundation’s in-house magazine, Science Nation . Seven
cute little goat kids were on show. Three of them were transgenic for the spider
silk gene, we were told, and the rest not; the clear message being that there
were no discernible differences between spider-goats and normal goats.
A year and a half later, the
spider goat is hyped as a marvel of the new ‘synthetic biology’ beyond genetic
engineering . Another video sequence features a somewhat dazed BBC reporter
invited to an ordinary farm to meet “absolutely regular” friendly spider-goats,
again indistinguishable from ordinary goats, to dispel any negative image one
might have of “frankenstein” animals .
At around the same time, Dutch
artist Jalila Essaidi, along with Forensic Genomics Consortium Netherlands, was
given an award of €25 000 for her idea to create bullet-proof human skin –
one-up on the spider-silk bulletproof vest - by incorporating the spider-silk
into human skin in culture, or maybe to genetically engineer humans to produce
the spider silk protein in the skin [6-8]? A third video sequence shows how
human skin grown in culture at Leiden University Medical Centre and impregnated
with spider silk from spider-goats and worms produced at the University of Utah
in the United States stopped a specially slowed- down bullet, though not one
shot at normal speed. An exhibition was mounted at the National Museum of
Natural History in Leiden, the Netherlands.
Why was such a revolting idea
worth pursuing? In her press release, Essaidi said : “I want to explore the
social, political, ethical and cultural issues surrounding safety.” By safety,
I think she meant the safety of humans being shot at. “The project leads to
aesthetically very impressing and fascinating results.” She concluded.
Spider silk is indeed a marvel,
and the spider-goat is surely a worthy instrument for bringing it to us, is it
No peer-reviewed scientific paper available
I tried to locate the scientific paper describing the
creation of the transgenic goat, but drew a complete blank. Science Nation
put me in touch with the scientist who did the work, Randolph Lewis at the
University of Wyoming, Laramie.
Lewis wrote in an e-mail message
: “The best information on the goats themselves is
the patent by Nexia Biotechnologies and they never published a paper from that
patent.” But the patent , I soon discovered, was on producing the silk
polypeptide and contained nothing on the creation of the transgenic goats.
the spider-goat was headline news almost 10 years ago. Nexia was the
Canadian biotech company trying to sell spider silk from the transgenic goats.
But the venture failed because the spider silk was way below the quality of
natural silk , and the company went out of business.
to my question as to whether his goats were cloned, Lewis said  that they
only have a couple of cloned goats done by somatic cell nuclear transfer. And
those were themselves cloned from initial goats created by transformation of
embryos with the spider silk transgene. “All the rest are from breeding both
transgenic does to normal bucks and transgenic bucks to normal does. We
maintain the herd as hemi-zygous [with only one copy of the transgene] to
maintain a reasonable level of spider silk protein in the milk.” He said. “Certainly
with nearly 10 years of having the transgenic goats there is nothing that can
distinguish the normal from the transgenic goats as our herd has both in it.”
So, the spider goats seen on
video were all bred from the couple of cloned goats, and were all hemizygous,
which at least avoided the deaths, abnormalities and suffering involved. However,
the ethical issue remains. It is hardly acceptable to exploit animals in this
way, particularly as more successful and acceptable alternatives already exist
(see later). It is worse than breeding animals for their fur, as the female’s
milk will not be available or suitable for nurturing the young.
Also, the biosafety dimension
cannot be swept under the carpet. Transgenic animals not only carry the stated
foreign genes (in the case of the transgenic goats, the spider silk genes), the
genes are delivered in vectors that often contain other sequences from viruses
and bacteria including antibiotic resistance genes, which often remain in the
transgenic animals, but we do not know what these are. There is
no report in the scientific literature or anywhere else that reports the
characterization of the transgenic sequences in the spider-goats’ genome.
Lewis is clearly aware of other
ways of producing spider silk, as he informs me in another e-mail: “We currently are producing the spider silk protein in E.
coli, the goats and in silkworms. We are pursuing all three as production
systems with specific applications targeted for each system as they each have
advantages and disadvantages.” But he did not elaborate what the advantages and
much spider protein is produced in the goat’s milk? Lewis wrote : “Our
goats range from 1-4 g/L and the best goats are producing 4-5L/day. We only
milk for 180d per lactation although many dairy goats go to 300 days per
lactation. So each goat can produce about 1.5 kg of spider silk protein per
of what Lewis told me about the spider-goats is in the scientific literature or
any other publicly available reports. I did e-mail Science Nation via
their website, copied to the National Science Foundation - which funds the
spider-goat project - asking if promoting unpublished, non-peer-reviewed
science was their policy, but have so far received no reply.
Surplus goats for our dinner table?
Lewis and colleagues are clearly aware of the biosafety
issue. In a paper published online in October 2011 , they remarked that
regulations for the disposal of genetically engineered animals are strict due
to concern for their inappropriate introduction into the food chain. “Nontransgenic
animals that give birth to transgenic offspring are treated as if they are
transgenic due to concern of fetal cells crossing the placental barrier and
residing in the other (fetal-maternal microchimerism). Determining whether or
not fetal-fetal or fetal-maternal transfer of DNA or cells occurs during gestation
is critical to effectively protect the public without culling animals that pose
In that paper, Lewis and
colleagues examined blood from 5 nontransgenic dams that carried transgenic
offspring using PCR sensitive enough to detect the presence of spider silk
transgene at 1 to 100 000 dilution (approximately 90 cells per millilitre of
blood), and could not detect any signal. Similarly, transfers between
transgenic and non-trangenic foetuses were undetectable. Further, they found no
ectopic (out of place) expression of spider silk genes in the heart, lung,
liver and brain. Nevertheless, they admit that the findings do not rule out
ectopic expression of the spider silk gene in other untested tissues and fluids
or the transfer of DNA and cells between foetus and mother or between foetuses.
And more studies with a larger sample must be carried out.
What the paper did reveal was the
intention to pass surplus animals into the food chain, which is neither ethical
nor safe ( Cloned
Meat and Milk Coming, SiS 50). Not least because we still do not
know what foreign sequences are in the transgenic animals apart from the spider
silk gene in general terms. All the transgenic sequences, including the spider
gene, are potentially harmful, especially if they end up in the genome of our
cells. Horizontal transfer of transgenic DNA is the most underestimated hazard
of genetic engineering, but it can indeed happen ( Scientists
Discover New Route for GM-gene 'Escape', SiS 50).
Moreover, the spider-goats may look indistinguishable from normal goats, but that does not mean they are the same biochemically and physiologically. The transgenic goats have never
been characterized at any level, nor have they been risk assessed for the
production of a transgenic herd. The legality of the transgenic herd itself is
surely in question.
There are 3 comments on this article so far. Add your comment
|Todd Millions Comment left 22nd February 2012 08:08:22|
Important overveiw of a matter never discussed.As well as the vexed mixing and carcass disposal issues(arc pyrosis anyone?),Has any comparision even being done on normal worm and spider silk for the intended use?Spider silk collected for textiles has being done since 1860's(brazil),and silk cannons go back to the Han dynasty at least(same design-wire wound 20" barrels for royal navy were tested after WWI).So as well as feathers in resin armour,with or without silk reinforcement(or paper)-do comparisions exist?I would rate this as important as the same armour tech is applicable too aircraft and other vechile construction of which our industries and designers are woefully backwards and structurally ignorant(Gordon and see;Hercules J model).
|maewan ho Comment left 22nd February 2012 10:10:27|
Thanks Todd for interesting information. Some of the issues you bring up will be discussed in two other articles in the series. Please look out for them.
|ellen Comment left 1st February 2013 15:03:39|
Another example of the human arrogance. Just bec. it can be done, it should be done, is the human motto. What about the integrity of the goat? Nothing is sacred in the human enterprise. If it benefits humans, it is good, that is the thinking. This attitude is why we have arrived at the point of making the earth uninhabitable for humans and every other living thing.