Cisgenesis

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Potatoes after treatment with Phytophthora infestans. The normal potatoes have blight but the cisgenic potatoes are healthy Cisgenicpotatoes.JPG
Potatoes after treatment with Phytophthora infestans . The normal potatoes have blight but the cisgenic potatoes are healthy

Cisgenesis is a product designation for a category of genetically engineered plants. A variety of classification schemes have been proposed [1] that order genetically modified organisms based on the nature of introduced genotypical changes, rather than the process of genetic engineering.

Contents

Cisgenesis (etymology: cis = same side; and genesis = origin) is one term for organisms that have been engineered using a process in which genes are artificially transferred between organisms that could otherwise be conventionally bred. [2] [3] Genes are only transferred between closely related organisms. [4] Nucleic acid sequences must be isolated and introduced using the same technologies that are used to produce transgenic organisms, making cisgenesis similar in nature to transgenesis. The term was first introduced in 2000 by Henk J. Schouten and Henk Jochemsen, [5] and in 2004 a PhD thesis by Jan Schaart of Wageningen University in 2004, discussing making strawberries less susceptible to Botrytis cinerea .

In Europe, currently, this process is governed by the same laws as transgenesis. While researchers at Wageningen University in the Netherlands feel that this should be changed and regulated in the same way as conventionally bred plants, other scientists, writing in Nature Biotechnology, have disagreed. [3] In 2012 the European Food Safety Authority (EFSA) issued a report with their risk assessment of cisgenic and intragenic plants. They compared the hazards associated with plants produced by cisgenesis and intragenesis with those obtained either by conventional plant breeding techniques or transgenesis. The EFSA concluded that "similar hazards can be associated with cisgenic and conventionally bred plants, while novel hazards can be associated with intragenic and transgenic plants." [6]

Cisgenesis has been applied to transfer of natural resistance genes to the devastating disease Phytophthora infestans in potato [7] and scab ( Venturia inaequalis ) in apple. [8] [9]

Cisgenesis and transgenesis use artificial gene transfer, which results in less extensive change to an organism's genome than mutagenesis, which was widely used before genetic engineering was developed. [10]

Some people believe that cisgenesis should not face as much regulatory oversight as genetic modification created through transgenesis as it is possible, if not practical, to transfer alleles among closely related species even by traditional crossing. The primary biological advantage of cisgenesis is that it does not disrupt favorable heterozygous states, particularly in asexually propagated crops such as potato, which do not breed true to seed. One application of cisgenesis is to create blight resistant potato plants by transferring known resistance loci wild genotypes into modern, high yielding varieties. [11]

The Dutch government has proposed to exclude cisgenic plants from the European GMO Regulation, in view of the safety of cisgenic plants compared to classically bred plants, and their contribution to durable food production. [12]

A related classification scheme proposed by Kaare Nielsen is: [1]

Source of genetic modificationGenetic variability via conventional breedingGenetic distance
IntragenicWithin genomePossibleLow
FamigenicSpecies in the same familyPossible
LinegenicSpecies in the same lineageImpossible
TransgenicUnrelated speciesImpossible
XenogenicLaboratory-designed genesImpossibleHigh

Diagram

A diagram comparing the genetic changes achieved through conventional plant breeding, transgenesis and cisgenesis Breeding transgenesis cisgenesis.svg
A diagram comparing the genetic changes achieved through conventional plant breeding, transgenesis and cisgenesis

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<span class="mw-page-title-main">Biotechnology</span> Use of living systems and organisms to develop or make useful products

Biotechnology is a multidisciplinary field that involves the integration of natural sciences and engineering sciences in order to achieve the application of organisms, cells, parts thereof and molecular analogues for products and services.

<span class="mw-page-title-main">Genetically modified maize</span> Genetically modified crop

Genetically modified maize (corn) is a genetically modified crop. Specific maize strains have been genetically engineered to express agriculturally-desirable traits, including resistance to pests and to herbicides. Maize strains with both traits are now in use in multiple countries. GM maize has also caused controversy with respect to possible health effects, impact on other insects and impact on other plants via gene flow. One strain, called Starlink, was approved only for animal feed in the US but was found in food, leading to a series of recalls starting in 2000.

<span class="mw-page-title-main">Genetically modified organism</span> Organisms whose genetic material has been altered using genetic engineering methods

A genetically modified organism (GMO) is any organism whose genetic material has been altered using genetic engineering techniques. The exact definition of a genetically modified organism and what constitutes genetic engineering varies, with the most common being an organism altered in a way that "does not occur naturally by mating and/or natural recombination". A wide variety of organisms have been genetically modified (GM), including animals, plants, and microorganisms.

<span class="mw-page-title-main">Genetic engineering</span> Manipulation of an organisms genome

Genetic engineering, also called genetic modification or genetic manipulation, is the modification and manipulation of an organism's genes using technology. It is a set of technologies used to change the genetic makeup of cells, including the transfer of genes within and across species boundaries to produce improved or novel organisms. New DNA is obtained by either isolating and copying the genetic material of interest using recombinant DNA methods or by artificially synthesising the DNA. A construct is usually created and used to insert this DNA into the host organism. The first recombinant DNA molecule was made by Paul Berg in 1972 by combining DNA from the monkey virus SV40 with the lambda virus. As well as inserting genes, the process can be used to remove, or "knock out", genes. The new DNA can be inserted randomly, or targeted to a specific part of the genome.

Agricultural biotechnology, also known as agritech, is an area of agricultural science involving the use of scientific tools and techniques, including genetic engineering, molecular markers, molecular diagnostics, vaccines, and tissue culture, to modify living organisms: plants, animals, and microorganisms. Crop biotechnology is one aspect of agricultural biotechnology which has been greatly developed upon in recent times. Desired trait are exported from a particular species of Crop to an entirely different species. These transgene crops possess desirable characteristics in terms of flavor, color of flowers, growth rate, size of harvested products and resistance to diseases and pests.

<i>Phytophthora infestans</i> Species of single-celled organism

Phytophthora infestans is an oomycete or water mold, a fungus-like microorganism that causes the serious potato and tomato disease known as late blight or potato blight. Early blight, caused by Alternaria solani, is also often called "potato blight". Late blight was a major culprit in the 1840s European, the 1845–1852 Irish, and the 1846 Highland potato famines. The organism can also infect some other members of the Solanaceae. The pathogen is favored by moist, cool environments: sporulation is optimal at 12–18 °C (54–64 °F) in water-saturated or nearly saturated environments, and zoospore production is favored at temperatures below 15 °C (59 °F). Lesion growth rates are typically optimal at a slightly warmer temperature range of 20 to 24 °C.

<span class="mw-page-title-main">Genetically modified food</span> Foods produced from organisms that have had changes introduced into their DNA

Genetically modified foods, also known as genetically engineered foods, or bioengineered foods are foods produced from organisms that have had changes introduced into their DNA using various methods of genetic engineering. Genetic engineering techniques allow for the introduction of new traits as well as greater control over traits when compared to previous methods, such as selective breeding and mutation breeding.

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<span class="mw-page-title-main">Genetically modified food controversies</span> Controversies over GMO food

Genetically modified food controversies are disputes over the use of foods and other goods derived from genetically modified crops instead of conventional crops, and other uses of genetic engineering in food production. The disputes involve consumers, farmers, biotechnology companies, governmental regulators, non-governmental organizations, and scientists. The key areas of controversy related to genetically modified food are whether such food should be labeled, the role of government regulators, the objectivity of scientific research and publication, the effect of genetically modified crops on health and the environment, the effect on pesticide resistance, the impact of such crops for farmers, and the role of the crops in feeding the world population. In addition, products derived from GMO organisms play a role in the production of ethanol fuels and pharmaceuticals.

<span class="mw-page-title-main">Gene targeting</span> Genetic technique that uses homologous recombination to change an endogenous gene

Gene targeting is a biotechnological tool used to change the DNA sequence of an organism. It is based on the natural DNA-repair mechanism of Homology Directed Repair (HDR), including Homologous Recombination. Gene targeting can be used to make a range of sizes of DNA edits, from larger DNA edits such as inserting entire new genes into an organism, through to much smaller changes to the existing DNA such as a single base-pair change. Gene targeting relies on the presence of a repair template to introduce the user-defined edits to the DNA. The user will design the repair template to contain the desired edit, flanked by DNA sequence corresponding (homologous) to the region of DNA that the user wants to edit; hence the edit is targeted to a particular genomic region. In this way Gene Targeting is distinct from natural homology-directed repair, during which the ‘natural’ DNA repair template of the sister chromatid is used to repair broken DNA. The alteration of DNA sequence in an organism can be useful in both a research context – for example to understand the biological role of a gene – and in biotechnology, for example to alter the traits of an organism.

<span class="mw-page-title-main">Genetically modified animal</span> Animal that has been genetically modified

Genetically modified animals are animals that have been genetically modified for a variety of purposes including producing drugs, enhancing yields, increasing resistance to disease, etc. The vast majority of genetically modified animals are at the research stage while the number close to entering the market remains small.

<span class="mw-page-title-main">Genetically modified mammal</span>

Genetically modified mammals are mammals that have been genetically engineered. They are an important category of genetically modified organisms. The majority of research involving genetically modified mammals involves mice with attempts to produce knockout animals in other mammalian species limited by the inability to derive and stably culture embryonic stem cells.

<span class="mw-page-title-main">Genetically modified tomato</span>

A genetically modified tomato, or transgenic tomato, is a tomato that has had its genes modified, using genetic engineering. The first trial genetically modified food was a tomato engineered to have a longer shelf life, which was on the market briefly beginning on May 21, 1994. The first direct consumption tomato was approved in Japan in 2021. Primary work is focused on developing tomatoes with new traits like increased resistance to pests or environmental stresses. Other projects aim to enrich tomatoes with substances that may offer health benefits or be more nutritious. As well as aiming to produce novel crops, scientists produce genetically modified tomatoes to understand the function of genes naturally present in tomatoes.

<span class="mw-page-title-main">Regulation of genetic engineering</span> Overview of the regulation of genetic engineering

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Genetic engineering in the European Union has varying degrees of regulation.

<span class="mw-page-title-main">Bintje</span> Potato variety

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<span class="mw-page-title-main">History of genetic engineering</span>

Genetic engineering is the science of manipulating genetic material of an organism. The first artificial genetic modification accomplished using biotechnology was transgenesis, the process of transferring genes from one organism to another, first accomplished by Herbert Boyer and Stanley Cohen in 1973. It was the result of a series of advancements in techniques that allowed the direct modification of the genome. Important advances included the discovery of restriction enzymes and DNA ligases, the ability to design plasmids and technologies like polymerase chain reaction and sequencing. Transformation of the DNA into a host organism was accomplished with the invention of biolistics, Agrobacterium-mediated recombination and microinjection. The first genetically modified animal was a mouse created in 1974 by Rudolf Jaenisch. In 1976 the technology was commercialised, with the advent of genetically modified bacteria that produced somatostatin, followed by insulin in 1978. In 1983 an antibiotic resistant gene was inserted into tobacco, leading to the first genetically engineered plant. Advances followed that allowed scientists to manipulate and add genes to a variety of different organisms and induce a range of different effects. Plants were first commercialized with virus resistant tobacco released in China in 1992. The first genetically modified food was the Flavr Savr tomato marketed in 1994. By 2010, 29 countries had planted commercialized biotech crops. In 2000 a paper published in Science introduced golden rice, the first food developed with increased nutrient value.

<span class="mw-page-title-main">Genetically modified tree</span> Tree whose DNA has been modified using genetic engineering techniques

A genetically modified tree is a tree whose DNA has been modified using genetic engineering techniques. In most cases the aim is to introduce a novel trait to the plant which does not occur naturally within the species. Examples include resistance to certain pests, diseases, environmental conditions, and herbicide tolerance, or the alteration of lignin levels in order to reduce pulping costs.

New Breeding Techniques (NBT), also named New Plant Engineering Techniques, are a suite of methods that could increase and accelerate the development of new traits in plant breeding. These new techniques, often involve 'genome editing' whose intention is to modify DNA at specific locations within the plants' genes so that new traits and properties are produced in crop plants.

Gene stacking is the combination of more than one gene for plant disease resistance, or crop productivity, or other horticultural traits. In plant breeding traditionally that means breeding those genes in, but increasingly also can mean genetic engineering. This can be achieved a few different ways, and gene pyramiding is one of those methods. Stacking of transgenes is yet more difficult than stacking natural genes, but especially in the case of pest resistance genes which require a significant financial investment to insert, is advantageous over other methods. Pathosystems with rapid evolution in the pathogen have long been considered good targets of stacking, to broaden and prolong resistance.

References

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  2. Cisgenesis definitions cisgenesis.com
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  4. MacKenzie D (2 August 2008). "How the humble potato could feed the world". New Scientist (2667): 30–33.
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  8. Vanblaere T, Flachowsky H, Gessler C, Broggini GA (January 2014). "Molecular characterization of cisgenic lines of apple 'Gala' carrying the Rvi6 scab resistance gene". Plant Biotechnol. J. 12 (1): 2–9. doi: 10.1111/pbi.12110 . PMID   23998808.
  9. Joshi SG, Schaart JG, Groenwold R, Jacobsen E, Schouten HJ, Krens FA (April 2011). "Functional analysis and expression profiling of HcrVf1 and HcrVf2 for development of scab resistant cisgenic and intragenic apples". Plant Mol. Biol. 75 (6): 579–91. doi:10.1007/s11103-011-9749-1. PMC   3057008 . PMID   21293908.
  10. Schouten, H.; Krens, F.; Jacobsen, E. (2006). "Do cisgenic plants warrant less stringent oversight?". Nature Biotechnology. 24 (7): 753. doi: 10.1038/nbt0706-753 . PMID   16841052.
  11. Jacobsen, E.; Schouten, H. J. (2008). "Cisgenesis, a New Tool for Traditional Plant Breeding, Should be Exempted from the Regulation on Genetically Modified Organisms in a Step by Step Approach". Potato Research. 51: 75–88. doi:10.1007/s11540-008-9097-y. Free version Archived 2015-09-23 at the Wayback Machine
  12. "Brief aan Eurocommissaris d.d. 18 december 2013 over Nieuwe veredelingstechnieken in de biotechnologie" [Letter to Commissioner dated December 18, 2013 on new breeding techniques in biotechnology] (in Dutch). 2014-01-06.