"David Hare-Scott" wrote in message
...

"Oz" wrote in message
...
David Hare-Scott writes

True there are no certainties but given the amount of time we
have been
doing it and the number of cases of development of new
varieties through
selective breeding mean that we have reasonable confidence in
the kinds
of
results that will be obtained.

Hardly...

Toxic potatoes (solanins)
Eczema celery (psilorins)
Lethal courgettes (cucubins)

have all been bred in in recent decades and have come to
market or very
nearly so (potatoes). These are just the ones one hears about.


So you are saying there are cases of selective breeding
producing vegetables
with toxins. This may or may not be so, solanins are naturally
occuring
toxins that may develop in all potatos and I cannot find any
reference to
psilorins or cucubins, so please supply some references.

If these cases are as you say what is your point? Are you
saying this mean
that selective breeding is a seriously flawed technique that
should be
abandoned?
============================
Reading comprehension problems too, eh? I don't think anyone
said that at all. The comments are that selective breeding isn't
necessarily safer than others. In some of these cases, since
'normal' breeding techniques need no safety testing unlike
biotechniques, products can make it to market that are dangerous.



Given the benefits that have accrued over the history of mankind
you have a long way to go to prove that. If not what are you
saying?
===================================
That the current kneejerk reaction to bio-techniques are
disingenuous.



David

http://www.alternative-doctor.com/al...lanttoxins.htm

Alternative-Doctor Allergy and Overload Pages


Natural toxins in foodstuffs

To those who think "herbal" means safe, natural and nurturing, I like to
point out that deadly nightshade (belladonna), opium, hemlock and
digitalis are all herbs €“ but very dangerous indeed!

In fact Nature has seen fit to endow a number of plants with the
capacity to synthesize substances that are toxic to humans and other
animals. Ingesting them may produce unpleasant consequences which are
not allergic but may become confused with an allergy. As I reported in
THE FOOD ALLERGY PLAN (Unwins, London, 1985), humans are probably able
to tolerate the majority of foods only because of the discovery of fire,
which cooks away toxins (although several plant toxins are heat-stable).

Farmers and veterinarians, who are more advanced in clinical ecology
than many doctors, have known for years that animals become sick if they
graze on certain types of plant (for example, bulls become enraged if
they eat loco weed €“ 'loco' being Spanish for crazy). Many plant
substances are toxic to humans in quite small quantities, including
deadly nightshade, acorns and hemlock. Ricin, the toxic principle in
caster seeds (Ricinus communis), is one of the most poisonous substances
known: a minute drop on a needle at the tip of an umbrella was used in
an infamous political assassination on the streets of London in 1978.

The fact is that all plants, including edible ones, contain quantities
of poisons. Carrots, for example, contain a nerve toxin: caratotoxin.
And someone once pointed out that if cabbage had to undergo the tests
that drugs are now subjected to before being pronounced fit for humans,
it wouldn't pass. Obviously, most often the amounts of poison in foods
are tolerable. Toxicity is a matter of degree.

There are a number of interesting groups of plants toxins in our food
supply. To understand them a little may help you work out some
mystifying food reactions that defy even the advice given here in this
book!

Lectins

Lectins are large protein molecules; they are toxic and also mimic
allergies. Lectins are widespread and may be up to 20 per cent of the
protein content of plants, especially of seeds and pulses. They have the
curious property of imitating antigen-antibody reactions without
actually sensitizing the immune system.

Anti-enzymes

These interfere with body enzymes such as trypsin (a protein digestive
enzyme). In experimental animals this interference has been shown to
cause retarding of growth, abnormal hypertrophy (enlargement) of the
pancreas and, in the case of prolonged feeding, even the formation of
cancer of the pancreas. Soya-bean protein derivatives have been shown to
retain some of this effect, leading to concern that infants fed on soya
milk might suffer growth retardation.

Goitrogens

Goitrogens are substances causing goiter or thyroid enlargement. Soya-
bean extract is in this category and goiters have been seen in human
infants fed with soya milk. Iodine appears to counter act this effect,
so infant soya milks are fortified with iodide as a precautionary
measure.

Goitrogens are a common constituent of plans belonging to the Crucifer
family (cabbage, turnip, swede, broccoli, cauliflower, kale brussel
sprout, rape and mustard seed). An epidemic goiter seen in Tasmania is
probably due to milk from cows fed on kale and turnips.

Oestrogens

There are naturally occurring oestrogenic compounds in many plants.
These heat-stable compounds are capable of eliciting an oestrogenic
response (feminization) in experimental animals. Recently much interest
has focused on so-called "phyto-oestrogens", some women like to use
these substances in the belief that they are somehow a natural
alternative to medication for hormone imbalances. This is partly
deluded, in that pseudo-oestrogens in plants are not the human hormone.
It is possible to manufacture natural human hormone, such as
progesterone from plant sources (such as diascorea from the wild yam)
but this requires a whole factory manufacturing process and chemical
formulations: not what I personally accept as a "natural" substances.

Moreover excess oestrogens are bad for males and equally harmful to
women already suffering from oestrogen dominance, a condition where
oestrogen is not balanced by opposing progesterone, causing bloating,
water retention and extreme mood changes. Therefore oestrogens,
naturally occurring in plants or not, are potentially toxic.

Nerve Toxins

Also known as cholinesterase inhibitors, these affect chiefly animals,
causing paalysis and sometimes death, though humans are occasionally
afflicted. Lathyrism, a condition associated with high intake of
lathyrus bean (chickpea family), is a kind of paralysis.

Poisons

These include prussic acid and its precursors, nicotine, solanin,
atropine and a host of others.

Antinutrients

Antinutrients are substances that interfere directly with the absorption
of vitamins, minerals and other nutrients.

Phytate occurs in several plant groups, particularly grains and also the
pulses. These are known to chelate, that is, combine with and remove,
valuable minerals such as calcium and magnesium and trace elements such
as zinc, copper and iron, which are vital for health.

Flatulence Factors

The pulses (peas and beans) are especially noted for this effect. The
cause is low molecular weight oligosaccharides (simple sugars), namely
raffinose and stachyose. Flatulence is generally attributed to the fact
that humans do not possess the enzyme alpha 1,6-galacto-sidase necessary
for breaking down these sugars. Blowing off? see flatulence section

Psychogenics

There is growing interest in drug-like substances in plans. Well-known
are the psychedelic substances such as those in marijuana and peyote
cactus; the coca plant gives rise to cocaine and the opium poppy is
notorious for its forbidden juices. But there have been opium-like
alkalodis called exorphins, and many other pharmacologically active
substances, found in plants. These may have beneficial effects as well
as unwanted ones.

Alkaloids

These are small organic molecules, usually comprising several carbon
rings with side chains, one or more of the carbon atoms being replaced
by a nitrogen (which confers the alkalinity). About 7 to 10 per cent of
all plants contain alkaloids, of which several thousand are now known.

Famous alkaloids include nicotine, quinine, strychnine, ergotamine and
atropine. The less toxic ones, such as caffeine, are used for pleasant
social effects. The powerful ones are hallucinogens (cannabis, LSD and
mescaline).

The well-known food allergy effect of addiction, where withdrawal from
the food causes unpleasant symptoms, may be due at least in part to the
addictive properties of alkaloids present in the food.

The action of alkaloids on the nervous system is generally to disrupt
electrochemical transmission at nerve junctions (synapses), either
preventing transmission (as in the case of the plant poison curare) or
enhancing it inappropriately (as, for example, physostigmine). Locoism,
referred to above, is of this latter class.

Outbreaks of food poisoning due to solanine (from potatoes), tomatine
(tomatoes) and dioscorine (yams) have all been reliably observed in
either humans or domestic animals. Death due to alkaloid overdose is
fortunately uncommon in humans; in Socrates' case (hemlock) it was
deliberate murder by the state. But subclinical alkaloid intoxication
occurs all the time. The 'edible' nightshades (potatoes, tomatoes,
capsicums, pepers) are especially rich sources, but cabbage, peppercorns
and many other foodstuffs are not far behind.

Exorphins

These are morphine-like peptides derived from partially digested grain,
milk and legume proteins. Pharmacologically they behave, when tested on
isolated tissues, very much like morphine, hence the name. It is
reasonable to propose that in people whose intestinal digestion of these
foodstuffs is incomplete, exorphins are absorbed and have the effect of
a small dose of an opiate drug-for example, patients who take wheat bran
and find their constipation gets worse. On the plus-side, the well-known
effect of pleasant somnolence after a meal is probably also due to
morphine-like activity.

Milk sickness

A disease known as milk sickness, characterized by weakness, nausea and
collapse, has occasionally reached epidemic proportions in certain parts
of the US. It probably caused the death of Abraham Lincoln's mother. The
name derives from the fact that the disease is brought on by drinking
milk from cow made ill with a disease known as the trembles. This was
eventually tracked down to the consumption, by cattle, of a plant known
as snake root (Eupatorium rugosum), containing the chemical tremetone.

Along the same lines, lupin alkaloids have been known to be transferred
to human beings via goat's milk. Birth abnormalities have been reported
and, significantly, lupin alkaloids have the same effect on goat
offspring.

Caffeine Family (Methylxanthines)

It is commonly forgotten that caffeine and theobromine (which occur in
tea and coffee) are toxic substances. Taken in sufficient quantities
they can cause cerebral oedema (so-called 'water on the brain),
convulsions and even death, though no one has ever been able to
establish tissue damage caused by chronic ingestion at normal levels.

Salicylates

Salicylates are aspirin-like chemicals that occur in many fruits and
vegetable. They tend to cause pharmacological rather than allergic
reactions. Adverse reactions are dose-related and only occur in
sensitive individuals who have a constitutional predisposition.

Hypertensive Substances

These are aromatic amino compounds such as serotonin and norepinephrine
(noradrenalin), which constrict blood vessels and thereby elevate the
blood-pressure. Such substances occur in chocolate, pineapple juice,
avocado, alcohol and cheese.

--
Oz
This post is worth absolutely nothing and is probably fallacious.

Use functions].
BTOPENWORLD address has ceased. DEMON address has ceased.

http://extoxnet.orst.edu/faqs/natural/plant1.htm

Natural Toxins in Food Plants
Some Examples of Natural Toxins
Each toxin is followed by a short list of some (not all) possible
sources
Enzyme inhibitors:
Cholinesterase inhibitors - in potatoes, tomatoes, and eggplant.
Protease inhibitors - in raw soybeans
Amylase inhibitors - in wheat flour
Tannins - in tea, coffee, and cocoa
Cyanogenic glycosides - in cassava.
Goitrogens (glucosinolates) - in Brassica species: cabbage, broccoli,
Brussels sprouts, etc.
Lectin proteins (phytohemagglutinins) - in red kidney beans
Lathyrogens - in chick peas and vetch
Pyrrolizidine alkaloids - in crops contaminated with weeds
Antivitamins:
Although not toxic per se, the anti-vitamins can cause problems as a
result of their interference with the function or absorption of
essential nutrients.
Anti-thiamin compounds - in mung beans, rice bran, beets, Brussels
sprouts
Avidin - in raw egg white

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

http://extoxnet.orst.edu/faqs/natural/phytoest.htm

'Endocrine Disrupters' (Phytoestrogens) in Food Plants

What are phytoestrogens?
What food crops have phytoestrogens in them?
Are phytoestrogens toxic to animals or humans?
Do phytoestrogens prevent cancer?
How much phytoestrogen is in some common food products?

More information on Endocrine Disrupters.
=================

http://extoxnet.orst.edu/faqs/natural/natpest.htm

Naturally Occurring Toxins used as Pesticides in Organic Farming

In many states, for produce to be labeled 'organic', the producer must
participate in a state certification program than ensures that only
natural pesticides have been used on the produce.

One of the most commonly used naturally-occurring pesticides are the
pyrethrins. The pyrethrins are natural insecticides extracted from
chrysanthemums.

Certification programs usually allow the use of pyrethrums, rotenone,
ryania, and sabadillia as insecticides on organic crops. Some of these
natural pesticides, such as ryania, have not been well studied as to
their toxicity.

In some cases, organically grown produce may contain more natural toxins
than produce grown using conventional pest management. For example,
apple juice from organically raised apples contains more patulin, a
probable carcinogen, than conventionally raised apples.(Jukes TH.
Organic apple juice no antidote for alar. J Am Dietetic Assoc
1990;90(3):371.)

With respect to environmental impact, there is evidence that a mixture
of organic and conventional pesticides may be more effective with less
harmful impact on the environment than purely organic regimes.(Kovach et
al )

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

etc etc

--
Oz
This post is worth absolutely nothing and is probably fallacious.

Use functions].
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David Hare-Scott writes
cucubins, so please supply some references.

curcubins are spelt differently by different researchers.
The main article on the poisoning in NZ is

1: Food Chem Toxicol. 1989 Aug;27(8):555-6.

Recent food poisonings from cucurbitacin in traditionally bred squash.

Unfortunately the paper is not on line.

--
Oz
This post is worth absolutely nothing and is probably fallacious.

Use functions].
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"rick" wrote in message news:EbUzf.6837
==========================
So, as a typical 'expert' here on usenet you'll dispute things
that you know nothing about, and won't even bother to research.
You must be veg*n, they're the willfully ignorant ones on most
subjects.


You made a claim that I hadn't heard anything about so I asked you to give
me a reference for it. Thankyou.


"...The potato contains a naturally occurring chemical that's
quite toxic, called a glycoalkyloid. Those glycoalkyloids in some
potatoes, as a matter of fact, have caused severe human
poisonings and near death. When you breed potatoes, it's possible
to breed in high levels of that toxin into a potato. And as a
matter of fact, there are a number of breeds of potatoes that
have high levels. Fortunately, they did not make the marketplace
for that reason.
Another great example of the risks of traditional breeding is
celery. Celery naturally contains a chemical, when it hits
sunlight, becomes toxic. There was a case in California where a
new variety of celery was bred. It had, unknown to the people who
bred it, high levels of this toxin in it. It was planted, and the
workers who harvested this came out with a very severe skin rash.
So normal kind of breeding can produce risks, just as any other
genetic or other kinds of breeding can produce risks..."

http://www.pbs.org/wgbh/harvest/etc/script.html

If you were really interested in knowledge, you could look things
up, but it appears you just want to remain willfully ignorant.


I am interested in you making a case to support your assertions. There are
quite enough crazys about who will claim anything to win an argument, I have
no idea if you fit that description or not, so why would I spend time
looking for what could be a chimera? Now that you have supplied some
material I have something to go on.

David

"Oz" wrote in message
...
David Hare-Scott writes
cucubins, so please supply some references.

curcubins are spelt differently by different researchers.
The main article on the poisoning in NZ is

1: Food Chem Toxicol. 1989 Aug;27(8):555-6.

Recent food poisonings from cucurbitacin in traditionally bred squash.

Unfortunately the paper is not on line.

--
Oz

Thanks for all the other refs anyway

David

"David Hare-Scott" wrote in message
...

"rick" wrote in message news:EbUzf.6837
==========================
So, as a typical 'expert' here on usenet you'll dispute things
that you know nothing about, and won't even bother to
research.
You must be veg*n, they're the willfully ignorant ones on most
subjects.


You made a claim that I hadn't heard anything about so I asked
you to give
me a reference for it. Thankyou.
============================
The point was that like many that tout organics, they do so from
propaganda. They, like you apparently, have done no real
research into organics, you just like the propaganda you've heard
an feel that that is all you need to know.
And, you're welcome...


"...The potato contains a naturally occurring chemical that's
quite toxic, called a glycoalkyloid. Those glycoalkyloids in
some
potatoes, as a matter of fact, have caused severe human
poisonings and near death. When you breed potatoes, it's
possible
to breed in high levels of that toxin into a potato. And as a
matter of fact, there are a number of breeds of potatoes that
have high levels. Fortunately, they did not make the
marketplace
for that reason.
Another great example of the risks of traditional breeding is
celery. Celery naturally contains a chemical, when it hits
sunlight, becomes toxic. There was a case in California where
a
new variety of celery was bred. It had, unknown to the people
who
bred it, high levels of this toxin in it. It was planted, and
the
workers who harvested this came out with a very severe skin
rash.
So normal kind of breeding can produce risks, just as any
other
genetic or other kinds of breeding can produce risks..."

http://www.pbs.org/wgbh/harvest/etc/script.html

If you were really interested in knowledge, you could look
things
up, but it appears you just want to remain willfully ignorant.


I am interested in you making a case to support your
assertions. There are
quite enough crazys about who will claim anything to win an
argument, I have
no idea if you fit that description or not, so why would I
spend time
looking for what could be a chimera? Now that you have
supplied some
material I have something to go on.
=====================
The point, again, was that the information is available to anyone
that wants the *facts* about that which they promote.
Most organic-only proponents do NO such research into all aspects
of the 'religion.' They feed off each other, reciting the same
lys and delusions over and over about benefits that aren't there.
As to why you wouldn't look into 'drawbacks' to a religion you
promote is the basis of all faiths.


David

"rick" wrote in message
k.net...

"David Hare-Scott" wrote in message
...

"rick" wrote in message news:EbUzf.6837
==========================
So, as a typical 'expert' here on usenet you'll dispute things
that you know nothing about, and won't even bother to
research.
You must be veg*n, they're the willfully ignorant ones on most
subjects.


You made a claim that I hadn't heard anything about so I asked
you to give
me a reference for it. Thankyou.
============================
The point was that like many that tout organics, they do so from
propaganda. They, like you apparently, have done no real
research into organics, you just like the propaganda you've heard
an feel that that is all you need to know.
And, you're welcome...


"...The potato contains a naturally occurring chemical that's
quite toxic, called a glycoalkyloid. Those glycoalkyloids in
some
potatoes, as a matter of fact, have caused severe human
poisonings and near death. When you breed potatoes, it's
possible
to breed in high levels of that toxin into a potato. And as a
matter of fact, there are a number of breeds of potatoes that
have high levels. Fortunately, they did not make the
marketplace
for that reason.
Another great example of the risks of traditional breeding is
celery. Celery naturally contains a chemical, when it hits
sunlight, becomes toxic. There was a case in California where
a
new variety of celery was bred. It had, unknown to the people
who
bred it, high levels of this toxin in it. It was planted, and
the
workers who harvested this came out with a very severe skin
rash.
So normal kind of breeding can produce risks, just as any
other
genetic or other kinds of breeding can produce risks..."

http://www.pbs.org/wgbh/harvest/etc/script.html

If you were really interested in knowledge, you could look
things
up, but it appears you just want to remain willfully ignorant.


I am interested in you making a case to support your
assertions. There are
quite enough crazys about who will claim anything to win an
argument, I have
no idea if you fit that description or not, so why would I
spend time
looking for what could be a chimera? Now that you have
supplied some
material I have something to go on.
=====================
The point, again, was that the information is available to anyone
that wants the *facts* about that which they promote.
Most organic-only proponents do NO such research into all aspects
of the 'religion.' They feed off each other, reciting the same
lys and delusions over and over about benefits that aren't there.
As to why you wouldn't look into 'drawbacks' to a religion you
promote is the basis of all faiths.


David





I have said nothing about organics but you want to lump me in with some
target group that you have in mind. You know nothing about me or my level
of knowledge except that I asked for more information on one topic but you
repeatedly say I am ignorant. You seem to be looking for someone to argue
with more than anything else - well it ain't me. You accuse others of
taking a religous attitude while displaying exactly that yourself.
Regardless of how much you might (or might not) know it's just too tedious
to try to have a conversation with you. End

David

David Hare-Scott writes

of rik

You accuse others of
taking a religous attitude while displaying exactly that yourself.
Regardless of how much you might (or might not) know it's just too tedious
to try to have a conversation with you. End

you implied that I was rik, which could hardly be further from the
truth. In fact I have rik killfiled for the reasons you give.

Given that I spent some time getting lengthy references for you it would
be very impolite to simply ignore them without a reply.

You can confirm oz is not rik by asking where I am known (eg ukba,
sciag).

--
Oz
This post is worth absolutely nothing and is probably fallacious.

Use functions].
BTOPENWORLD address has ceased. DEMON address has ceased.

"Oz" wrote in message
...
David Hare-Scott writes

of rik

You accuse others of
taking a religous attitude while displaying exactly that yourself.
Regardless of how much you might (or might not) know it's just too
tedious
to try to have a conversation with you. End

you implied that I was rik, which could hardly be further from the
truth. In fact I have rik killfiled for the reasons you give.

Given that I spent some time getting lengthy references for you it would
be very impolite to simply ignore them without a reply.

You can confirm oz is not rik by asking where I am known (eg ukba,
sciag).

--
Oz
This post is worth absolutely nothing and is probably fallacious.

Use functions].
BTOPENWORLD address has ceased. DEMON address has ceased.


I don't know where I implied you were rick, I don't think that you are. It
will take me some time to read the refs that you found me as I am busy
building a house right now and don't want to just skim though it all. I
will get back to you, please be patient.

David

Oz

I have now had a chance to read the material that you pointed me towards.
This is (in summary) what I have gathered from it.

1) There are a great many toxins present in plants including some plants
that are grown for food. No surprise there. Some writers go on to say that
it follows that "natural" doesn't necessarily mean safe. No surprise there
either. People have been poisoning themselves with plants for a long time
and the fad that anything called "natural" must be good is an invention of
the advertising world. Nobody knows what "natural" means in that context
anyway, probably nothing at all.

2) One such toxin is cucurbitacin which is found in squash and pumpkins.
There are cases reported of the amout of this toxin being increased through
selective breeding, some instances seem to have been deliberate in order to
create resistence to insects. I had trouble accessing original papers but
there is nothing improbable about that so I accept that it happened.

3) Also this article (that you quoted)
http://www.geo-pie.cornell.edu/issues/convtoxins.html
refers to the same kind of problem in potatos and celery (different toxins).
Once again I accept that it happened. What I don't accept is the author's
rather sweeping statement

"Conventionally-bred crop varieties may actually pose a greater risk from
increased plant toxins than genetically engineered plants."

I cannot see anywhere that he/she substantiates such a comparison. There is
NO attempt to evaluate the risks of either technique so I cannot see how
anyone can say one is more risky than the other. I take the point however
that being new GM plants are subject to much higher scrutiny and testing
than selectively bred varieties and that the presumption of safety of the
latter is by no means guaranteed. If you know of any articles on line where
the relative risks are evaluated I would be keen to see them.

What do I think of the relative risks? As I pointed out to start of the
thred with Genetic Engineering (GE) and Selective Breeding (SB) are both
Genetic Modification (GM). That does not say anything about their relative
safety. GE involves direct transfer of genetic material including that from
totally unrelated species. SB is the alteration of the frequency of
selected genes in the target population by breeding from organisms showing
favoured characteristic(s). In GE genes are directly modified, in SB
existing genes are selected in favour of others, there is no alteration of
the genes themselves. SB may select for a mutation but it does not create
mutations.

SB is traditional Darwinian evolution being directed by humans by choosing
the environment. By manipulating the environment we manipulate the gene
frequencies in the population much faster than otherwise and in directions
that would never be taken without human intervention. This is where nearly
all our cultivated plant and domesticated animal varieties came from.

Is the SB process 100% free of risk? No way. But as we are only playing
with the frequency of existing genes the scope for a bad result is limited.
If it wasn't people would have be getting poisoned far to often since
agriculture started and neither cultivated species nor the humans that
depend on them would be what they are today. The huge growth of human
population could never have happened if SB was very unsafe.

What about the risks of GE? To me it is an open question, one that we
should put many resources into answering so we can determine the real risks.
This needs to be done over a long period of time with plenty of redundant
cross checking by different parties. The probability of harm from the
technique in general and the safety of each given organism both need to be
studied carefully until we get a handle on it. I don't want to see our
foods end up like some "wonder drugs" that have been pushed out by big
business only to be withdrawn years later when the effects were fully
evaluated. How will a dangerous GE gene be "withdrawn" some years down the
track once it becomes widespread?

David

"David Hare-Scott" wrote in message
...


3) Also this article (that you quoted)
http://www.geo-pie.cornell.edu/issues/convtoxins.html
refers to the same kind of problem in potatos and celery (different
toxins).
Once again I accept that it happened. What I don't accept is the author's
rather sweeping statement

"Conventionally-bred crop varieties may actually pose a greater risk from
increased plant toxins than genetically engineered plants."

I cannot see anywhere that he/she substantiates such a comparison. There
is
NO attempt to evaluate the risks of either technique so I cannot see how
anyone can say one is more risky than the other. I take the point however
that being new GM plants are subject to much higher scrutiny and testing
than selectively bred varieties and that the presumption of safety of the
latter is by no means guaranteed.

But in making that statement you have agreed with the author. GM plants are
far more subject to scrutiny than conventional varieties which receive damn
all. Many conventional varieties we have been eating for generations would
never have recieved clearance had modern regulators been able to check and
ban them when they first appeared

--

Jim Webster.
Pat Gardiner, Five years raving about bent vets and still no result

David Hare-Scott writes

Oz

I have now had a chance to read the material that you pointed me towards.
This is (in summary) what I have gathered from it.

3) Also this article (that you quoted)
http://www.geo-pie.cornell.edu/issues/convtoxins.html
refers to the same kind of problem in potatos and celery (different toxins).
Once again I accept that it happened. What I don't accept is the author's
rather sweeping statement

"Conventionally-bred crop varieties may actually pose a greater risk from
increased plant toxins than genetically engineered plants."

I cannot see anywhere that he/she substantiates such a comparison.
There is
NO attempt to evaluate the risks of either technique so I cannot see how
anyone can say one is more risky than the other.

Actually that is incorrect. Significantly different varieties are
roughly checked but this would, for 'conventional', only be after
outcrossing with wild (or effectively wild) relations that may contain
(be known to contain) toxins. When crossing like this obviously the
first cross will contain 50% of the 'wild' species, which includes a lot
of unwanted genes most of which do unknown things. After multiple
crossing the breeder hopes to have selected the characteristics required
(pest resistance, colour, shape, whatever), but probably includes some
other 'wild' genes.

All (artificial) genetically modified crops in the west are checked in
feeding trials as far as this can be done. The one big advantage is they
know precisely the gene introduced and that they have introduced no
others. Which is, of course, why its such a valuable tool. It can take
decades to breed out the unwanted wild genes from a cultivar in the
conventional way.


I take the point however
that being new GM plants are subject to much higher scrutiny and testing
than selectively bred varieties and that the presumption of safety of the
latter is by no means guaranteed. If you know of any articles on line where
the relative risks are evaluated I would be keen to see them.

They were about, but when this was a hot topic some years ago.

What do I think of the relative risks? As I pointed out to start of the
thred with Genetic Engineering (GE) and Selective Breeding (SB) are both
Genetic Modification (GM). That does not say anything about their relative
safety. GE involves direct transfer of genetic material including that from
totally unrelated species. SB is the alteration of the frequency of
selected genes in the target population by breeding from organisms showing
favoured characteristic(s). In GE genes are directly modified, in SB
existing genes are selected in favour of others, there is no alteration of
the genes themselves.

Of course that's not quite right. In GE genes are not modified, they are
nicked (unmodified) from elsewhere and in SE we note many garden
varieties (eg cereals) are so packed with mutations and polyploidy that
they can no longer breed unaided with wild relatives.

SB may select for a mutation but it does not create
mutations.

Frankly an unknown selected mutation is quite a bit more hazardous than
a known artificially introduced gene. Is this splendidly pest resistant
variety a new mutation or a good selection? Ditto nice flavour? etc etc?

We actually don't know.

SB is traditional Darwinian evolution being directed by humans by choosing
the environment. By manipulating the environment we manipulate the gene
frequencies in the population much faster than otherwise and in directions
that would never be taken without human intervention. This is where nearly
all our cultivated plant and domesticated animal varieties came from.

I don't think so. Most of the really useful characteristics are
mutations. Just consider the grossly deformed maize plant with teosinte.
Heck it doesn't have male and female bits of flower at the top but has
the female bits grotesquely poking out half way down.

Is the SB process 100% free of risk? No way. But as we are only playing
with the frequency of existing genes the scope for a bad result is limited.

Unfortunately not. Mutations happen. They get spotted.

If it wasn't people would have be getting poisoned far to often since
agriculture started and neither cultivated species nor the humans that
depend on them would be what they are today. The huge growth of human
population could never have happened if SB was very unsafe.

Its more that plant breeding is pretty safe. Unfortunately we don't
actually know if our plant species are safe because most have never been
tested. In fact feeding to animals is probably the only real test and
the species fed is very limited. Even so most feeds are restricted in
the amounts that should be fed due to animals showing negative
reactions. Often the precise reasons are not known but the safe feeding
amounts are.

Some have been known in farming for A VeryLongTime. Not putting tupping
ewes on a clovery/leguminous sward is one very nice example but there
are others.

What about the risks of GE? To me it is an open question, one that we
should put many resources into answering so we can determine the real risks.
This needs to be done over a long period of time with plenty of redundant
cross checking by different parties.

's OK. Massive worldwide experiment feeding to humans and livestock
worldwide now in its 15th year without problems.


--
Oz
This post is worth absolutely nothing and is probably fallacious.

Use functions].
BTOPENWORLD address has ceased. DEMON address has ceased.

"Jim Webster" wrote in message
...

"David Hare-Scott" wrote in message
...

NO attempt to evaluate the risks of either technique so I cannot see how
anyone can say one is more risky than the other. I take the point
however
that being new GM plants are subject to much higher scrutiny and testing
than selectively bred varieties and that the presumption of safety of
the
latter is by no means guaranteed.

But in making that statement you have agreed with the author. GM plants
are
far more subject to scrutiny than conventional varieties which receive
damn
all.

Yes but it seems quite reasonable to me that it is so.

Many conventional varieties we have been eating for generations would
never have recieved clearance had modern regulators been able to check and
ban them when they first appeared


This is very hard to get a handle on as I cannot see any attempt to quantify
the problems with 'conventional' crops. Yes some cases of toxins being
created/augmented are reported but how significant is that in the overall
scheme of things? If it is only a rare siuation why would you want to
impose regulation on it.

David

"Oz" wrote in message
...
David Hare-Scott writes

Oz

I have now had a chance to read the material that you pointed me towards.
This is (in summary) what I have gathered from it.

3) Also this article (that you quoted)
http://www.geo-pie.cornell.edu/issues/convtoxins.html
refers to the same kind of problem in potatos and celery (different
toxins).
Once again I accept that it happened. What I don't accept is the
author's
rather sweeping statement

"Conventionally-bred crop varieties may actually pose a greater risk from
increased plant toxins than genetically engineered plants."

I cannot see anywhere that he/she substantiates such a comparison.
There is
NO attempt to evaluate the risks of either technique so I cannot see how
anyone can say one is more risky than the other.

Actually that is incorrect.

Sorry where are the evaluations of risk of the two techniques are the
quantitative comparison of them?

Significantly different varieties are
roughly checked but this would, for 'conventional', only be after
outcrossing with wild (or effectively wild) relations that may contain
(be known to contain) toxins. When crossing like this obviously the
first cross will contain 50% of the 'wild' species, which includes a lot
of unwanted genes most of which do unknown things. After multiple
crossing the breeder hopes to have selected the characteristics required
(pest resistance, colour, shape, whatever), but probably includes some
other 'wild' genes.

All (artificial) genetically modified crops in the west are checked in
feeding trials as far as this can be done. The one big advantage is they
know precisely the gene introduced and that they have introduced no
others. Which is, of course, why its such a valuable tool. It can take
decades to breed out the unwanted wild genes from a cultivar in the
conventional way.


I take the point however
that being new GM plants are subject to much higher scrutiny and testing
than selectively bred varieties and that the presumption of safety of the
latter is by no means guaranteed. If you know of any articles on line
where
the relative risks are evaluated I would be keen to see them.

They were about, but when this was a hot topic some years ago.


I think we have to leave it there then since I didn't see such.

What do I think of the relative risks? As I pointed out to start of the
thred with Genetic Engineering (GE) and Selective Breeding (SB) are both
Genetic Modification (GM). That does not say anything about their
relative
safety. GE involves direct transfer of genetic material including that
from
totally unrelated species. SB is the alteration of the frequency of
selected genes in the target population by breeding from organisms
showing
favoured characteristic(s). In GE genes are directly modified, in SB
existing genes are selected in favour of others, there is no alteration
of
the genes themselves.

Of course that's not quite right. In GE genes are not modified,

Ok I didn't express this very well but it doesn't alter my point that one is
direct manipulation of genes and the other of their frequencies in the
population. And I want to know why my tomatos can't be made to taste like
salmon too! :-)

they are
nicked (unmodified) from elsewhere and in SE we note many garden
varieties (eg cereals) are so packed with mutations and polyploidy that
they can no longer breed unaided with wild relatives.

SB may select for a mutation but it does not create
mutations.

Frankly an unknown selected mutation is quite a bit more hazardous than
a known artificially introduced gene. Is this splendidly pest resistant
variety a new mutation or a good selection? Ditto nice flavour? etc etc?

We actually don't know.


So what do you recommend?

SB is traditional Darwinian evolution being directed by humans by
choosing
the environment. By manipulating the environment we manipulate the gene
frequencies in the population much faster than otherwise and in
directions
that would never be taken without human intervention. This is where
nearly
all our cultivated plant and domesticated animal varieties came from.

I don't think so. Most of the really useful characteristics are
mutations.

This may be so today, I don't know what modern plant breeders get up to in
any detail. But considering the history of edible plant breeding I would
expect that our ancestors selected for size, flavour, etc as a primary goal.
Most of those sorts of qualities are covered by many genes not single
mutations, which is why takes so many generations to develop them. Does it
really matter if such qualities are single or multi factorial? In both
cases SB is still pushing around genotypes in populations by selecting
phenotypes.

Just consider the grossly deformed maize plant with teosinte.
Heck it doesn't have male and female bits of flower at the top but has
the female bits grotesquely poking out half way down.

Is the SB process 100% free of risk? No way. But as we are only playing
with the frequency of existing genes the scope for a bad result is
limited.

Unfortunately not. Mutations happen. They get spotted.

If it wasn't people would have be getting poisoned far to often since
agriculture started and neither cultivated species nor the humans that
depend on them would be what they are today. The huge growth of human
population could never have happened if SB was very unsafe.

Its more that plant breeding is pretty safe. Unfortunately we don't
actually know if our plant species are safe because most have never been
tested.

Hang on, we eat them all the time, isn't that a pretty large scale test?

In fact feeding to animals is probably the only real test and
the species fed is very limited. Even so most feeds are restricted in
the amounts that should be fed due to animals showing negative
reactions. Often the precise reasons are not known but the safe feeding
amounts are.

Some have been known in farming for A VeryLongTime. Not putting tupping
ewes on a clovery/leguminous sward is one very nice example but there
are others.

What about the risks of GE? To me it is an open question, one that we
should put many resources into answering so we can determine the real
risks.
This needs to be done over a long period of time with plenty of redundant
cross checking by different parties.

's OK. Massive worldwide experiment feeding to humans and livestock
worldwide now in its 15th year without problems.


I must be ultra conservative on such issues.

I am running short of hours again so we might have to leave it until another
day. Oz I think we have both said what we can about this interesting topic.

David