The Experts below are selected from a list of 312 Experts worldwide ranked by ideXlab platform
Maria Zapiola - One of the best experts on this subject based on the ideXlab platform.
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Gene Flow from glyphosate-resistant crops
Pest Management Science, 2008Co-Authors: Carol Mallory-smith, Maria ZapiolaAbstract:Gene Flow from transgenic glyphosate-resistant crops can result in the adventitious presence of the transGene, which may negatively impact markets. Gene Flow can also produce glyphosate-resistant plants that may interfere with weed management systems. The objective of this article is to review the Gene Flow literature as it pertains to glyphosate-resistant crops. Gene Flow is a natural phenomenon not unique to transgenic crops and can occur via pollen, seed and, in some cases, vegetative propagules. Gene Flow via pollen can occur in all crops, even those that are considered to be self-pollinated, because all have low levels of outcrossing. Gene Flow via seed or vegetative propagules occurs when they are moved naturally or by humans during crop production and commercialization. There are many factors that influence Gene Flow; therefore, it is difficult to prevent or predict. Gene Flow via pollen and seed from glyphosate-resistant canola and creeping bentgrass fields has been documented. The adventitious presence of the transGene responsible for glyphosate resistance has been found in commercial seed lots of canola, corn and soybeans. In General, the glyphosate-resistant trait is not considered to provide an ecological advantage. However, regulators should consider the examples of Gene Flow from glyphosate-resistant crops when formulating rules for the release of crops with traits that could negatively impact the environment or human health.
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Review Gene Flow from glyphosate-resistant crops
2008Co-Authors: Carol Mallory-smith, Maria ZapiolaAbstract:Gene Flow from transgenic glyphosate-resistant crops can result in the adventitious presence of the transGene, which may negatively impact markets. Gene Flow can also produce glyphosate-resistant plants that may interfere with weed management systems. The objective of this article is to review the Gene Flow literature as it pertains to glyphosate-resistant crops. Gene Flow is a natural phenomenon not unique to transgenic crops and can occur via pollen, seed and, in some cases, vegetative propagules. Gene Flow via pollen can occur in all crops, even those that are considered to be self-pollinated, because all have low levels of outcrossing. Gene Flow via seed or vegetative propagules occurs when they are moved naturally or by humans during crop production and commercialization. There are many factors that influence Gene Flow; therefore, it is difficult to prevent or predict. Gene Flow via pollen and seed from glyphosate-resistant canola and creeping bentgrass fields has been documented. The adventitious presence of the transGene responsible for glyphosate resistance has been found in commercial seed lots of canola, corn and soybeans. In General, the glyphosate-resistant trait is not considered to provide an ecological advantage. However, regulators should consider the examples of Gene Flow from glyphosate-resistant crops when formulating rules for the release of crops with traits that could negatively impact the environment or human health. 2008 Society of Chemical Industry
Joaquima Messeguer - One of the best experts on this subject based on the ideXlab platform.
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Gene Flow assessment in transgenic plants
Plant Cell Tissue and Organ Culture, 2003Co-Authors: Joaquima MesseguerAbstract:In most of the important crops in the world, Gene Flow between cultivars and between wild and weedy relatives has always taken place. Factors influencing this Gene Flow, such as the mating system, mode of pollination, mode of seed dispersal and the particular characteristics of the habitat where the crops grow, are difficult to evaluate and in consequence, the quantification of Gene Flow is not easy. TransGene Flow from engineered crops to other cultivars or to their wild and weedy relatives is one of the major concerns in relation to the ecological risks associated with the commercial release of transgenic plants. With transgenic crops it is important to quantify this Gene Flow and to try to establish strategies to control or minimise it, taking into account the possible ecological effect of the newly introduced Genes, whether advantageous or disadvantageous. The use of transgenic plants has proven to be an effective tool to quantify the Gene Flow to other cultivars of the same species or to wild and weedy relatives in all crops analysed. Here we review the major studies in this area, and conclude that the potential risk of Gene Flow has to be assessed case by case and caution is necessary when making General conclusions.
Carol Mallory-smith - One of the best experts on this subject based on the ideXlab platform.
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Gene Flow from Herbicide-Resistant Crops: It's Not Just for TransGenes
Journal of Agricultural and Food Chemistry, 2010Co-Authors: Carol Mallory-smith, Elena Sanchez OlguinAbstract:Gene Flow was raised as one of the first issues related to the development and release of Genetically engineered (GE) crops. Gene Flow has remained a topic of discussion for more than 20 years and is still used as an argument against the release of transgenic crops. With respect to herbicide-resistant crops, Gene Flow does not differ whether the herbicide resistance trait is introduced via Genetic engineering or via conventional breeding techniques. Conventional breeding and Genetic engineering techniques have been used to produce herbicide resistance in many of the same crop species. In addition, conventional breeding has been used to produce a broader range of herbicide-resistant crops than have been Genetically engineered for herbicide resistance. Economic, political, and social concerns center on the breeding technique, but the results of Gene Flow for weed management are the same irrespective of breeding technique. This paper will focus on Gene Flow from nonGE herbicide-resistant crops in North America.
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Gene Flow from glyphosate-resistant crops
Pest Management Science, 2008Co-Authors: Carol Mallory-smith, Maria ZapiolaAbstract:Gene Flow from transgenic glyphosate-resistant crops can result in the adventitious presence of the transGene, which may negatively impact markets. Gene Flow can also produce glyphosate-resistant plants that may interfere with weed management systems. The objective of this article is to review the Gene Flow literature as it pertains to glyphosate-resistant crops. Gene Flow is a natural phenomenon not unique to transgenic crops and can occur via pollen, seed and, in some cases, vegetative propagules. Gene Flow via pollen can occur in all crops, even those that are considered to be self-pollinated, because all have low levels of outcrossing. Gene Flow via seed or vegetative propagules occurs when they are moved naturally or by humans during crop production and commercialization. There are many factors that influence Gene Flow; therefore, it is difficult to prevent or predict. Gene Flow via pollen and seed from glyphosate-resistant canola and creeping bentgrass fields has been documented. The adventitious presence of the transGene responsible for glyphosate resistance has been found in commercial seed lots of canola, corn and soybeans. In General, the glyphosate-resistant trait is not considered to provide an ecological advantage. However, regulators should consider the examples of Gene Flow from glyphosate-resistant crops when formulating rules for the release of crops with traits that could negatively impact the environment or human health.
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Review Gene Flow from glyphosate-resistant crops
2008Co-Authors: Carol Mallory-smith, Maria ZapiolaAbstract:Gene Flow from transgenic glyphosate-resistant crops can result in the adventitious presence of the transGene, which may negatively impact markets. Gene Flow can also produce glyphosate-resistant plants that may interfere with weed management systems. The objective of this article is to review the Gene Flow literature as it pertains to glyphosate-resistant crops. Gene Flow is a natural phenomenon not unique to transgenic crops and can occur via pollen, seed and, in some cases, vegetative propagules. Gene Flow via pollen can occur in all crops, even those that are considered to be self-pollinated, because all have low levels of outcrossing. Gene Flow via seed or vegetative propagules occurs when they are moved naturally or by humans during crop production and commercialization. There are many factors that influence Gene Flow; therefore, it is difficult to prevent or predict. Gene Flow via pollen and seed from glyphosate-resistant canola and creeping bentgrass fields has been documented. The adventitious presence of the transGene responsible for glyphosate resistance has been found in commercial seed lots of canola, corn and soybeans. In General, the glyphosate-resistant trait is not considered to provide an ecological advantage. However, regulators should consider the examples of Gene Flow from glyphosate-resistant crops when formulating rules for the release of crops with traits that could negatively impact the environment or human health. 2008 Society of Chemical Industry
Norman C Ellstrand - One of the best experts on this subject based on the ideXlab platform.
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When Gene Flow really matters: Gene Flow in applied evolutionary biology
Evolutionary Applications, 2016Co-Authors: Norman C Ellstrand, Loren H RiesebergAbstract:In the last half century, Gene Flow has moved from relative obscurity to a well‐recognized component of evolution. Gene Flow, the successful transfer of alleles from one population to another, is now known to vary considerably among species, populations, and individuals as well as over time. It frequently occurs at rates sufficient to play an important evolutionary role for populations of both animals and plants (Ellstrand 2014; Yakimowski and Rieseberg 2014; Arnold 2015). Gene Flow does not automatically come to mind in the context of evolutionary applications. When the senior author shared the idea of a Special Issue on Gene Flow in Applied Evolution with a colleague, she asked, “What else is there besides crop breeding?” Considerably more, as we shall soon see. Gene Flow is important in a remarkable variety of applied situations. This Special Issue presents some representative points in the galaxy of applied topics in which Gene Flow plays a key role. The number of possible topics precludes an exhaustive treatment. Likewise, while we acknowledge that non‐sexual Gene Flow (horizontal transfer) has considerable applied and evolutionary significance in prokaryotes and eukaryotes (e.g. Koonin et al. 2001; Richardson and Palmer 2007; Arnold 2015), the topic is so large, we deem it worthy of separate treatment.
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Current knowledge of Gene Flow in plants: implications for transGene Flow
Philosophical Transactions of the Royal Society B, 2003Co-Authors: Norman C EllstrandAbstract:Plant evolutionary biologists' view of Gene Flow and hybridization has undergone a revolution. Twenty-five years ago, both were considered rare and largely inconsequential. Now Gene Flow and hybridization are known to be idiosyncratic, varying with the specific populations involved. Gene Flow typically occurs at evolutionarily significant rates and at significant distances. Spontaneous hybridization occasionally has important applied consequences, such as stimulating the evolution of more aggressive invasives and increasing the extinction risk for rare species. The same problems have occurred for spontaneous hybridization between crops and their wild relatives. These new data have implications for transgenic crops: (i) for most crops, Gene Flow can act to introduce engineered Genes into wild populations; (ii) depending on the specific engineered Gene(s) and populations involved, Gene Flow may have the same negative impacts as those observed for traditionally improved crops; (iii) Gene Flow's idiosyncratic nature may frustrate management and monitoring attempts; and (iv) intercrop transGene Flow, although rarely discussed, is equally worthy of study.
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Gene Flow among seed plant populations
New Forests, 1992Co-Authors: Norman C EllstrandAbstract:Gene Flow is a critical determinant of population Genetic structure, playing an important role in both evolutionary and applied plant population Genetics. Four methods have been used to estimate rates of Gene Flow among plant populations. I review and reconcile the data collected by these methods. The following Generalization emerges: although Gene Flow varies substantially among species, populations, seasons, and even individual plants, at physical isolation distances of hundreds to thousands of meters, Gene Flow levels are frequently sufficient to counteract Genetic drift and moderate levels of directional selection. This pattern suggests the Genetic structure of natural plant populations is more dynamic than Generally supposed. Furthermore, substantial and variable Gene Flow has implications for plant breeding, conservation Genetics, and the potential for the escape of engineered Genes.
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Gene Flow by pollen implications for plant conservation Genetics
Oikos, 1992Co-Authors: Norman C EllstrandAbstract:The absence of Gene Flow, Genetic isolation, is frequently emphasized in conservation Genetics. However, the presence of Gene Flow can play an equally important role in determining the Genetic fate of populations. Here, I first review what is known of patterns of Gene Flow by pollen. Gene Flow by pollen is often substantial among plant populations. I next review the expectations for Gene Flow patterns in the small populations typical of endangered species. Then, I consider what role Gene Flow can play in plant conservation Genetics. Depending on the specific situation, such Gene Flow could be either beneficial or detrimental. Geographically disjunct populations might not always be as reproductively isolated as previously thought, and thereby less vulnerable to detrimental drift-based processes (...)
Ziheng Yang - One of the best experts on this subject based on the ideXlab platform.
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Defining Species When There is Gene Flow.
Systematic Biology, 2020Co-Authors: Xiyun Jiao, Ziheng YangAbstract:Whatever one's definition of species, it is Generally expected that individuals of the same species should be Genetically more similar to each other than they are to individuals of another species. Here we show that in the presence of cross-species Gene Flow, this expectation may be incorrect. We use the multispecies coalescent model with continuous-time migration or episodic introgression to study the impact of Gene Flow on Genetic differences within and between species and highlight a surprising but plausible scenario in which different population sizes and asymmetrical migration rates cause a Genetic sequence to be on average more closely related to a sequence from another species than to a sequence from the same species. Our results highlight the extraordinary impact that even a small amount of Gene Flow may have on the Genetic history of the species. We suggest that contrasting long-term migration rate and short-term hybridization rate, both of which can be estimated using Genetic data, may be a powerful approach to detecting the presence of reproductive barriers and to define species boundaries.
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The Impact of Cross-Species Gene Flow on Species Tree Estimation.
Systematic Biology, 2020Co-Authors: Xiyun Jiao, Tomas Flouri, Bruce Rannala, Ziheng YangAbstract:Recent analyses of genomic sequence data suggest cross-species Gene Flow is common in both plants and animals, posing challenges to species tree estimation. We examine the levels of Gene Flow needed to mislead species tree estimation with three species and either episodic introgressive hybridization or continuous migration between an outgroup and one ingroup species. Several species tree estimation methods are examined, including the majority-vote method based on the most common Gene tree topology (with either the true or reconstructed Gene trees used), the UPGMA method based on the average sequence distances (or average coalescent times) between species, and the full-likelihood method based on multilocus sequence data. Our results suggest that the majority-vote method based on Gene tree topologies is more robust to Gene Flow than the UPGMA method based on coalescent times and both are more robust than likelihood assuming a multispecies coalescent (MSC) model with no cross-species Gene Flow. Comparison of the continuous migration model with the episodic introgression model suggests that a small amount of Gene Flow per Generation can cause drastic changes to the Genetic history of the species and mislead species tree methods, especially if the species diverged through radiative speciation events. Estimates of parameters under the MSC with Gene Flow suggest that African mosquito species in the Anopheles gambiae species complex constitute such an example of extreme impact of Gene Flow on species phylogeny. [IM; introgression; migration; MSci; multispecies coalescent; species tree.].
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the impact of cross species Gene Flow on species tree estimation
bioRxiv, 2019Co-Authors: Xiyun Jiao, Tomas Flouri, Bruce Rannala, Ziheng YangAbstract:ABSTRACT Recent analyses of genomic sequence data suggest cross-species Gene Flow is common in both plants and animals, posing challenges to species tree inference. We examine the levels of Gene Flow needed to mislead species tree estimation with three species and either episodic introgressive hybridization or continuous migration between an outgroup and one ingroup species. Several species tree estimation methods are examined, including the majority-vote method based on the most common Gene tree topology (with either the true or reconstructed Gene trees used), the UPGMA method based on the average sequence distances (or average coalescent times) between species, and the full-likelihood method based on multi-locus sequence data. Our results suggest that the majority-vote method is more robust to Gene Flow than the UPGMA method and both are more robust than likelihood assuming a multispecies coalescent (MSC) model with no cross-species Gene Flow. A small amount of introgression or migration can mislead species tree methods if the species diverged through speciation events separated by short time intervals. Estimates of parameters under the MSC with Gene Flow suggest the Anopheles gambia African mosquito species complex is an example where Gene Flow greatly impacts species phylogeny.
