01-24-2014, 05:21 PM
From the GMO Myths and Truths
"1.3.3. Is mutation breeding widely used?
Mutation breeding is not a widely used or central part of crop breeding, though a few crop varieties have apparently benefited from it. A database maintained by the UN Food and Agriculture Organisation and the International Atomic Energy Agency keeps track of plant varieties that have been generated using mutation breeding and by cross-breeding with a mutant plant.6 There are only around 3,000 such plant varieties. This number includes not only crop plants but also
GMO Myths and Truths 13
ornamental plants.9 It also includes not only the direct mutant varieties, but also varieties bred by crossing the mutants with other varieties by conventional breeding. Thus the actual number of primary mutant varieties is significantly lower than 3000.
Some commercially important traits have come out of mutation breeding, such as the semi-dwarf trait in rice, the high oleic acid trait in sunflower, the semi-dwarf trait in barley, and the low-linolenic acid trait in canola (oilseed rape).9,10,11
But conventional breeding, in contrast, has produced millions of crop varieties. The Svalbard seed vault in the Arctic contains over 400,000 seed varieties,12 which are estimated to represent less than one-third of our most important crop varieties.13 So relatively speaking, mutation breeding is of only marginal importance in crop development.
The reason mutation breeding is not more widely used is that the process of mutagenesis is risky, unpredictable, and does not efficiently generate beneficial mutations. Studies on fruit flies suggest that about 70% of mutations will have damaging effects on the functioning of the organism, and the remainder will be either neutral or weakly beneficial.14
Because of the primarily harmful effects of mutagenesis, the genetic code is structured to minimize the impacts of mutations and organisms have DNA repair mechanisms to repair mutations. In addition, regulatory agencies around the world are supposed to minimise or eliminate exposure to manmade mutagens.
In plants as well as fruit flies, mutagenesis is a destructive process. As one textbook on plant breeding states, “Invariably, the mutagen kills some cells outright while surviving plants display a wide range of deformities.”15 Experts conclude that most such induced mutations are harmful, and lead to unhealthy and/or infertile plants.15,16 Occasionally, mutagenesis gives rise to a previously unknown feature that may be beneficial and can be exploited.
The process of screening out undesirable traits and identifying desirable ones for further breeding has been likened to “finding a needle in a haystack”.15 The problem is that only certain types of mutations, such as those affecting shape or colour, are obvious to the eye. These plants can easily be discarded or kept for further breeding as desired. But other more subtle changes may not be obvious, yet may nonetheless have important impacts on the health or performance of the plant. Such changes can only be identified by expensive and painstaking testing.15
A report by the UK government’s GM Science Review Panel concluded that mutation breeding “involves the production of unpredictable and undirected genetic changes and many thousands, even millions, of undesirable plants are discarded in order to identify plants with suitable qualities for further breeding.”17
In retrospect, it is fortunate that mutation breeding has not been widely used because that has reduced the likelihood that this risky technology could have generated crop varieties that are toxic, allergenic, or reduced in nutritional value."
- Armed citizens provide security of a free State.
"1.3.3. Is mutation breeding widely used?
Mutation breeding is not a widely used or central part of crop breeding, though a few crop varieties have apparently benefited from it. A database maintained by the UN Food and Agriculture Organisation and the International Atomic Energy Agency keeps track of plant varieties that have been generated using mutation breeding and by cross-breeding with a mutant plant.6 There are only around 3,000 such plant varieties. This number includes not only crop plants but also
GMO Myths and Truths 13
ornamental plants.9 It also includes not only the direct mutant varieties, but also varieties bred by crossing the mutants with other varieties by conventional breeding. Thus the actual number of primary mutant varieties is significantly lower than 3000.
Some commercially important traits have come out of mutation breeding, such as the semi-dwarf trait in rice, the high oleic acid trait in sunflower, the semi-dwarf trait in barley, and the low-linolenic acid trait in canola (oilseed rape).9,10,11
But conventional breeding, in contrast, has produced millions of crop varieties. The Svalbard seed vault in the Arctic contains over 400,000 seed varieties,12 which are estimated to represent less than one-third of our most important crop varieties.13 So relatively speaking, mutation breeding is of only marginal importance in crop development.
The reason mutation breeding is not more widely used is that the process of mutagenesis is risky, unpredictable, and does not efficiently generate beneficial mutations. Studies on fruit flies suggest that about 70% of mutations will have damaging effects on the functioning of the organism, and the remainder will be either neutral or weakly beneficial.14
Because of the primarily harmful effects of mutagenesis, the genetic code is structured to minimize the impacts of mutations and organisms have DNA repair mechanisms to repair mutations. In addition, regulatory agencies around the world are supposed to minimise or eliminate exposure to manmade mutagens.
In plants as well as fruit flies, mutagenesis is a destructive process. As one textbook on plant breeding states, “Invariably, the mutagen kills some cells outright while surviving plants display a wide range of deformities.”15 Experts conclude that most such induced mutations are harmful, and lead to unhealthy and/or infertile plants.15,16 Occasionally, mutagenesis gives rise to a previously unknown feature that may be beneficial and can be exploited.
The process of screening out undesirable traits and identifying desirable ones for further breeding has been likened to “finding a needle in a haystack”.15 The problem is that only certain types of mutations, such as those affecting shape or colour, are obvious to the eye. These plants can easily be discarded or kept for further breeding as desired. But other more subtle changes may not be obvious, yet may nonetheless have important impacts on the health or performance of the plant. Such changes can only be identified by expensive and painstaking testing.15
A report by the UK government’s GM Science Review Panel concluded that mutation breeding “involves the production of unpredictable and undirected genetic changes and many thousands, even millions, of undesirable plants are discarded in order to identify plants with suitable qualities for further breeding.”17
In retrospect, it is fortunate that mutation breeding has not been widely used because that has reduced the likelihood that this risky technology could have generated crop varieties that are toxic, allergenic, or reduced in nutritional value."
- Armed citizens provide security of a free State.