13 internautes sur 16 ont trouvé ce commentaire utile
Jeffrey L. Blackwell
- Publié sur Amazon.com
This book attempts a modern history of crop improvements, focusing upon plant genetic engineering. It describes the techniques used by molecular biologists to splice selective genes into plant DNA to create better crops. It is a well-deserved commemorative to several great crop scientists of our era. They have quietly saved the lives of millions. It is also a primer in genetic engineering techniques and effects for a general reader.
While intended for a general audience, it is poorly written for a generalist. Although there is sufficient info for a generalist to get an understanding of genetic engineering as applied to GM crops, the book's organization makes the reader work harder than should have been necessary.
1) Sequence of argument: The sequence of scientific break-throughs wasn't conceptually sequential. For example, a DNA illustration was presented before Mendel's Laws or Darwin's natural selection mechanism were explained. This conceptual jumping is a poor organization for introducing a complex subject to a general reader.
2)The introduction began strong -- the promise of Golden Rice as a GMC that could prevent blindness due to deficiency of Vitamin A. However, it should have transitioned into what the book would present: step-by-step chapters to build a conceptual model of plant breeding from Darwin-Mendel to DNA to techniques and effects of GMCs. All the while showing that genetic splicing is not so different from mutagenic chemical treatments or irradiation. These are points to make a case for GMCs being as safe as these earlier techniques to create useful mutations. While some chapters were historical, these could have been written as both historical and conceptual steps, i.e., Mendel's laws as applied by cross-hybridization techniques.
3) Chapter transitions should serve as 'bookmarks in main argument.' Chapter transitions were not effective in reiterating major points of earlier chapters.
Nor were chapter introductions developed as descriptions of what the chapter would present.
4)The authors did not provide sufficient background for generalists (name-dropping isn't the same as background unless you are a biologist). Often when they did provide a breakthrough technique or experiment as background this was interrupted by historical anecdotes & background bio about the experimenter.
5) Many of these anecdotes should be footnotes. Otherwise, these digress from the point being made & its relation to chapter argument (and to main argument). But these anecdotes & oral history are interesting history and make the book worth reading!
6) Content What authors de-emphasis, obscure or omit usually identify their point-of-view. The main argument does present the criticisms of an intelligent group of opponents to GMCs but it addresses these in pieces diffused throughout several chapters. These seem to be minor criticisms without a coherent Big Picture overview. The authors' pro-GMC argument is not impaired rhetorically so they privilege their position as the only Big Picture point-of-view. From other books on GMCs I have found that GMCs' critics have a legitimate point. GMCs as implemented by multinational agribusiness (MNAs)have negative consequences and losers. When / if the GMC research funder, the seed seller, and the crop buyer is the same MNA, there is a near monopolistic control of the implementation of GMCs to the detriment of small farmers (both in US & abroad).
7) A better pro-GMC Big Picture would present these criticisms as an intelligent point-of-view held by many regulatory groups, international NGOs /aid providers, and advocates for small farmers. A sophisticated pro-GMC argument would advocate a rational regulatory process to protect losers from monopolistic abuses of MNAs. (perhaps only tough enforcement of existing anti-trust laws is adequate)
This topic is exciting and potentially of interest to a wide audience -- high school science students, undergrads, and concerned citizens. Mendel in the Kitchen has solid historical info and deserved a much more coherent presentation.
In design, criticism is a better design, so here is my outline, perhaps I wanted a different book:
I The Big Picture
Introduction: Thoreau -- making soil say 'beans', 2nd modern quote: potential of nitrogen-fixing GMCs, controversies surrounding Golden Rice
i) The problem -- population, starvation & famine, scarcity of resources (water, land, fertilizer) & pollution
ii) The solution -- Genetically Modified Crops -- betacaratene-enhanced GMCs, nitrogen-fixing GMCs, salt-tolerant GMCs, etc.
iii) Important misconceptions -- natural mutations vs 'traumatized' mutations, i.e., irradiation vs gene-splicing (all of the several techniques)
iv) Trade-offs and necessary regulation & protection of public
II Episodes in Evolution of Plant Breeding Techniques
Chap 1 -- a) From Gathering to Farming (early argument of J Diamond),
b) Case-studies of Wheat, Corn, from wild to cultivated (as descriptive without introducing mutation procedures) these could be then be examples of crop breeding techniques as various techniques are described later.
c) Columbian Exchange: Linnaeus' taxonomy, New World crops gene pool
Chap 2 -- Darwin & Mendel: natural selection and selective breeding
a) Voyage of Beagle (transition from Columbian Exchange)
b) Origins' idea of natural selection
c) evidence from plants,
d) 'black box' of precisely how transfer occurs
B) Mendel's Laws of Inheritance: Plant genetics as an exact science
a) laws of inheritance explain in precise math previous 'black box'
b) the combined Darwin-Mendel paradism becomes dominant in biology
C)Darwin-Mendel paradigm applications :experiments & theory of 1800s
Chap 3 -- Burbank as empiricist: experiments & practical achievement
Chap 4 -- Counter-case: Lysenko's disaster in Soviet collective agriculture, 1930s
Chap 5 -- What seeds need to produce high-yield crops -- Chemistry as applied to soils, fertilizers, pesticides, 1700 to 1940s (these become criteria for selective crop breeding)
Chap 6 -- McClintock's 'transposons' as jumping genes
Chap 7 -- The Green Revolutions: Borlaug & Khush /IRRI
A) shuttle breeding for better crops
B) post-WWII & cheap nitrogen-based fertilizers
C) development and export of pesticides & herbicides
D) 3rd World industrialization w/ tractors & irrigation
E) Rockefeller Fd.'s $ support, USAID, UN, govt. farm loans, price support
III GMC Revolution
Chap 8 -- Watson, Crick, others: DNA and prospect of gene splicing in plants
Intro: transgenesis vs cisgenesis ( not sure where to put this one)Cisgenesis -- using GM to insert flowering plant genes into other flowering plants. (Natural selection might have produced this mutation)
Transgenesis -- using GM to insert non-plant genes into flowering plant crops (This can only be done with gene splicing)
For transgenesis,i.e.,inserting a retrovirus gene or pig gene into a flowering plant, from a Darwinian point-of-view, there is a 'god in the gap' issue.
Millions of years of natural selection have produced the precise chromosome sequence that naturally occurring plants express. Much of GM does not disrupt this sequence. Cisgenesis inserts genes into crop plants which might have been introduced with non-GM breeding. The GM is a cost-saving convenience.
Transgenesis, i.e., inserting a retrovirus gene or pig gene into a flowering plant is radically different from the development of chromosomes through natural selection. The chemistry of the gene may be identical but how it interacts within a 'foreign' DNA sequence & in world ecosystems is undetermined. At least, some molecular biologists might admit that they really don't know what the long-term effects of these might be. (These may have unforeseen consequences, beneficial and /or harmful).
Chap 9 -- The Promise of GMC Revolution (Benefits)
a) techniques of genetic splicing
b) effects, i.e., betacaratene-enhanced GMCs
c) future prospects,i.e., nitrogen-fixing GMCs, salt-tolerant GMCs, etc.
IV Contemporary Controversies over GMC Risks
Chapter 10 -- Economic & Consumer Risks of GMCs
A) Potential for MNA monopolistic abuse
a)Europe's protection of small, less competitive farmers (under the guise of the 'dangers' of GMCs) vs U S's 'free-market' regulated support of multinational agribusiness (MNAs) & the demise of less competitive, small U S farmers
b) Africa's (Zambia) refusal to accept GMC aid. (influenced by European funders & Europe as Africa's main export market)This was simply irrational.
B)other issues of IRRI vs MNAs as tech delivery systems:
a) Although the prospects may be spectacular increases in food production, can urban poor afford to buy this surplus ? Displaced subsistence farmers, forced to migrate from rural to urban, increase these urban poor.
b)A realistic prospect of higher unemployment in agrarian-based 3rd world nations is a consequence. This increases unemployed urban poor & weakens stability.
c) In contrast, a crucial part of the Green Revolution of Borlaug & Khush (IRRI) was that its focus was not export cash crops like canola, etc. Because of this, it was less detrimental to small-scale & subsistence farmers.
- If MNAs are implementers, are critics correct to demand regulations that protect small farmers,limit extensive monocultures, require long-term test trials prior to marketing?
B) Consumers' Risks
a) Should GM foods be labeled in grocery aisle? (My note: Case-study of Big Tobacco of the 60s demonstrates that multinationals don't always use scientific evidence responsibly.)Consumers should have the right to choose, even if based upon misconception.
b) testing for alergens
c) Related issue: What kind of tests, how long in duration? Should tests results be provided before GMC-based foods are allowed to be sold?
C) Chapter 11 Ecological Risks of Production of GMC in Monocultures
a)low risks of non-flowering plant parts as food (allows sterile GM crops)Also, this may be possible for some kinds of self-pollinating plants within flower
b)Can flowering, full growth cycle GMCs become Superweeds? What makes GM plants especially 'fit to a design environment' may also make unintended mutations / cross breeds into superweeds. Issues of pollen flow, invasive GM plants, 'terminator sequences', w/ 2nd generation sterile male (pollen), fertile female GM plants) etc.
c) The frightening possibility, that somewhere in the world a bio-weapons lab is developing predators / defoliates, etc. targeted to specific GMCs. (Rebuttal: Whether we implement GMCs or not, the GM tech will, like highly virulent strains of small pox, eventually get to bad guys & bad govts.)
d) The related issue,especially when implemented by MNAs, unregulated monoculture production and prospect of larger famines when pests adapt. Need to regulate large scale agribusiness monoculture and have system for rotation. (Rebuttal: MNAs will do this in their own interests. Will they? MNAs often focus on short-term risky profit-taking. Externalities,like famine due to massive monoculture crop failure, the public will pay in event of calamity, whether in food aid or/and MNA bail-out).
e) If GMCs are safe, why is Golden Rice kept in a Level 4, high-risk facility at IRRI? This may be unnecessary but authors did not explain details.
f) Some genes spliced, i.e., Bacillus thurg., have been 'naturally-occuring' pesticides. Effects of a large increase of this non-biodegradeable toxin possible i) possible resistance eventually as pests adapt ii) build-up of Bt in soils
V The Bigger Picture w/ pros & cons, Risks /Benefits
Chap 12 -- Conclusions with graphs, statistics, maps, etc. -- a return to introduction with case for GMCs rebutting the issues raised in book, esp. Chaps 10 & 11. A list of GMC research by university, MNA, other non-profits. The authors argue that, due to dire global food prospects & the higher cost due to fossil fuel demands of today's crops, GMCs are worth these risks. (Some argue the Green Revolution's techniques produced this high fossil fuel-based agriculture). Is regulation by EPA adequate for ecological risk protection? Is FDA really protectiong consumers on this issue? What is USDA's role (field testing, etc.)? What happens in export markets, where govt. agencies are non-existent?
For the Big-Change GMCs, like Golden rice or Nitrogen-fixing GMCs,let us hope that these patents remain in the public university domain in conjunction with public interest non-profits like IRRI. If implemented by non-profits, like IRRI, the worst of these consequences may be avoided. This was the genius of the Green Revolution. PS: Wu & Butz, Rand Corp, The Future of GM Crops, is great read on topic
7 internautes sur 8 ont trouvé ce commentaire utile
- Publié sur Amazon.com
This book is among the most meticulously documented and well-written science texts I have ever had the pleasure of reading. While I do not presume to have read every book produced thus far on modern biotechnology or plant genetics, I will nevertheless wager that no one has done it better.
In some ways it is four books in one. The authors tackle the ancient history of biotechnology, predating even Gregor Mendel and his famous garden pea studies in the yard of his monastery in the 1860s. But they also recount Mendel's interest in the genetics of bees and mice, which few ever learn about.
The authors then follow the modern genomic advances by Crick and Watson, Cohen and Boyer, and all who came before, in between, and thereafter. They not only explain the moment-by-moment conceptual and laboratory development of these advances, but make every effort to teach the science along the way.
The latter part of the book reviews the political and sociological aspects of biotechnology in the modern world, offering unbiased, objective details before drawing the only possible conclusions. Simply put: Genetically modified plants are the answer to the world's potential food supply problems; organic agriculture as it is presently defined cannot contribute significantly to society's needs.
Genetic Engineering's Long History
Genetic engineering is not new. For nearly a century, scientists have been cloning pink grapefruit from a mutant strain discovered on a tree in Florida in 1907. Scientists developed the Red Rio grapefruit in 1968 by exposing grapefruit buds to thermal neutron radiation at Brookhaven National Laboratory.
The most significant changes in grains and advances in knowledge about crop genomes occurred many years ago. When we eat wheat, we consume varieties mutated by nuclear radiation. It is not known what happened to the genomes, but we have been eating this wheat safely for decades.
Today, with more extensive knowledge and new applications of the technologies resulting from genetic engineering, our scientists have more control over the genetic changes introduced, and their work is more precise than ever before.
Fedoroff and Brown methodically trace the development of nearly every major grain consumed by society today, providing details of their DNA mutations. They also trace the need for fertilizer and its early applications in the nineteenth century. For flower lovers, the complete story of Luther Burbank and his plant grafting techniques is noteworthy.
Roots of Green Revolution
Many readers will especially enjoy the full story of Norman Borlaug as it plays out on the pages of this book. Many people are aware that he won the Nobel Prize in 1971 for launching the Green Revolution, but few of us know the complete and wonderful details of his education, research, and teachings. And Borlaug's story is not yet complete: He still works full-time in this field at Texas A&M University, traveling the world more than 150 days a year ... at age 90.
A brief summary of Borlaug's Nobel Prize work is recorded in the book as follows:
"As Borlaug explained in the Nobel lecture, 'Through a series of crosses and re-crosses (of wheat) begun in 1954, dwarfness was incorporated into the superior, new-combination Mexican types, finally giving rise to a group, or so-called dwarf Mexican wheat varieties.' By changing the plant's architecture to emphasize a short, sturdy stalk, the dwarfness trait allowed the wheat to produce heavier seed heads given enough water and nitrogen without falling over in a breeze. In addition, the plants were not affected by length of day (and so could grow at a range of latitudes) and were highly resistant to wheat rusts. The result, in Borlaug's terms, was a 'yield blast-off.' A few seasons after the new variety was introduced Mexico became self-sufficient in wheat. When introduced into Pakistan and India, the wheat had the same yield-boosting effects."
Explanation of Genetics
Genetics is by no means an easy science to understand, and I will not say this book makes a simple primer that is easily understood. But it does make significant breakthroughs in genetics education. For me this was one such example:
"Genes can change, they can duplicate and delete, and genomes scramble. It is increasingly evident that what genes do depends more on what they are than where they are--although both a gene's immediate neighbors and its general genomic neighborhood can influence its expression. But evolution takes a long time--like the movement of tectonic plates. The evolution of a plant is measured in millions of years, not in the months it takes to grow a crop of corn."
Debunking Biotech Critics
The authors analyze in more detail than is warranted all the major technical charges made against biotech by its many detractors. With great precision they defeat each false claim without bias, never calling the opponents what this writer is inclined to label them.
No one has ever scientifically refuted the anti-biotech crowd as well as Fedoroff and Brown do in this book. Their patience in doing so is amazing.
Safety of Biotech Food
If you are interested in biotechnology and genetically modified foods, you have most likely read the stories of StarLink corn and monarch butterflies. But I promise you that you have never read the complete story of either of these.
StarLink corn is a biotech corn that was approved only for animal feed when some of it found its way into taco shells. Activist groups duped the media into reporting that this was causing widespread allergic reactions in people. Later, the Centers for Disease Control and Prevention (CDC) released a study showing that StarLink corn produced absolutely no adverse effects on people who had consumed it.
Similarly, activist groups duped the media into reporting that biotech corn fields were causing widespread monarch butterfly deaths. Later, EPA concluded that biotech corn poses very little risk to monarch butterflies.
The retelling of these fraud-filled scandals on the pages of Mendel in the Kitchen is alone worth the price of this book. Along the way you will learn precisely how grains that contain a gene that produces the protective Bacillus thuringiensis (Bt) bacterium work their damage upon unwanted insects ... and also why they cannot be harmful to man and other animals.
Fedoroff and Brown also do a great job explaining all the precautions that have been taken by the government and the biotech industry to ensure the pests they target with Bt seeds do not become resistant to the toxins generated by the plant. This concern is continually thrown up by the anti-biotech crowd with no scientific support.
Predominance of Natural Pesticides
The book's chapter on organic food, titled "The Organic Rule," is the best primer on organic agriculture that you will ever find. Again the authors exhibit a complete lack of bias. Until the final pages of the chapter, one would have no idea which, if any, side of the organic food issue the authors lean toward.
But in the end they evaluate their own data and make many very strong and persuasive statements regarding the inability of organic farming to supply the needs of a hungry world.
In this chapter they also summarize the many contributions of Bruce Ames in eliminating the concerns over trace amounts of agricultural pesticides in our food. More than 99 percent of the chemicals people eat are natural. Coffee, for example, contains more than a thousand different chemicals. Twenty-eight of those have been tested in rodent bioassays, and 19 have been found to be carcinogenic in mega doses fed to rats and mice.
Plants produce many natural pesticides. Seventy-one of these have been tested, and 37 are cancinogenic in mega quantities to some rodents. Ames proves in a variety of ways that these high-dose rodent bioassays have no relevance to the health of human beings.
Ames estimates Americans eat somewhere between 5,000 and 10,000 natural pesticides every day, ingesting 1,500 milligrams of such chemicals per person. That is about 10,000 times more than the 0.09 milligrams of synthetic pesticide they eat in conventionally grown food each day.
Ames concludes, "There is no convincing evidence that synthetic chemical pollutants are important as a cause of human cancer." He states emphatically, "if reducing synthetic pesticides makes fruits and vegetables more expensive, thereby decreasing consumption, then the cancer rate will increase, especially for the poor."
Organic Farming's Costs
People who argue for organic farming as a world-wide solution to hunger often overlook three points: organic farming makes food more expensive, requires that more land be put under cultivation, and requires that more hard, manual labor be performed to harvest the crops.
Fedoroff documents this very well. When explaining the organic growth of potatoes in Bolivia she quotes Per Pinstrup-Andersen, former director general of the International Food Policy Research Institute (IFPRI):
"To have enough manure, the organic farmers must either reduce the size of their potato fields or put more land to the plow. When the cost of the additional land is factored into the study, the figures for yield per hectare do not look so good. If we set aside the ecological risks of bringing more land under cultivation, organic farming may be a perfectly acceptable solution in regions with unused land that can be cultivated without damaging the environment." But, Fedoroff adds, "Such regions are becoming scarce."
Ebbe Schioler, a colleague of Pinstrup-Andersen at IFPRI, described the work environment of organic rice growers in Africa: "The weeds they faced were stout thistles, coarse grasses, large thick-leaved plants with tough stalks, and little bushes that produce powerful, deep-reaching root systems. The farmers use no herbicides. Everything is done by hand and hoe, and even though the children do their bit, it is still touch and go. It takes 40 days of sweating and straining each year to keep just one hectare of land weed-free."
Fedoroff concludes her chapter on organic farming as follows: "Suggestions that organic farming is appropriate for countries with high population pressure and limited arable land and water supplies sounds suspiciously like Marie Antoinette's famous statement, 'Let them eat cake.' Or as Peter Raven, head of the Missouri Botanical Garden, has noted, 'Organic agriculture is essentially what is practiced in sub-Saharan Africa today, and half of the people are starving, so it is clear that more [than organic techniques] is needed.'"
While "sustainable agriculture" is a term that hides its intention to promote organic farming, Mendel in the Kitchen tells the real facts about what we would logically conclude to be meant by the term--namely, using land wisely to feed the world.
Economist Indur Goklany has calculated that were we still using 1961 farm technology, we would need to put 82 percent of the Earth's land surface under cultivation ... rather than the 38 percent we actually use. Borlaug calculates that the Green Revolution has saved 20 million square miles of wilderness since 1950. Dennis Avery of The Hudson Institute has pointed out that the world's 16 million square miles of forest would all have to have been destroyed without modern agriculture.
The authors of Mendel in the Kitchen, in an effort to promote real sustainable agriculture, offer an excellent tutorial on reduced tillage and no-till farming. They point out that continuous cultivation has been a misguided bad habit driven by the desire to have pretty fields, the need to eliminate weeds before effective herbicides were available, and a lack of understanding of soil health.
Fedoroff correctly explains the basic reasons to reduce tillage on cropland: reduce runoff, increase soil moisture, eliminate soil erosion, improve soil tilth, increase carbon content, improve air quality, improve surface water quality, and increase wildlife habitat ... not to mention the saving on labor, fuel, and wear and tear on machinery.
Possible Future Breakthroughs
In the closing chapter, "Food For Thought," the authors open with a poignant quote from Dr. Florence Wambugu of the Kenyan Agricultural Research Institute. She said, "You people in the developed world are certainly free to debate the merits of genetically modified foods, but can we please eat first?"
In this chapter, readers are given more reasons for optimism about the future impacts of plant biotechnology than one could possibly imagine. Virtually all of the impediments to expanding crop yields around the world are linked to insufficient nitrogen fertilizer, inability to fix adequate quantities of carbon from the atmosphere while maintaining sufficient moisture uptake, or the inability to grow in soils high in salt or aluminum. These problems must be overcome if farmers' yields are to double or perhaps even triple to meet the demands of a human population that will reach 8 or 9 billion within 50 years and demand more and better food.
It seems unlikely the future holds another simple breakthrough, like the synergy between dwarfing genes and fertilizer that made the Green Revolution possible. But a breakthrough that enhances the use of nitrogen or the efficiency of photosynthesis or the use of soils previously toxic to growth could push yields up dramatically.
Mendel in the Kitchen may ultimately hasten the day of such breakthroughs. It could be used as a college textbook in biotechnology for a variety of courses focusing on science, history, and politics. If you have an interest in any one of these areas, the book is a wonderful read.
Jay Lehr, Ph.D. ([...]) is science director for The Heartland Institute.