GENE FLOW FROM DOMESTICATED SPECIES TO WILD RELATIVES: MIGRATION LOAD IN A MODEL OF MULTIVARIATE SELECTION

With the rapid adoption of transgenic crops, gene flow from transgenic crops to wild relatives through pollen dispersal is of significant concern and warrants both empirical and theoretical studies to assess the risk of introduction of transgenes into wild populations. We propose to use the (biased) voter model in a heterogeneous environment to investigate the effects of recurrent gene flow from transgenic crop to wild relatives. The model is defined on the d-dimensional integer lattice that is divided into two parts, Δ and Z d \ Δ. Individuals carrying the transgene and individuals carrying the wild type gene compete according to the evolution rules of a (biased) voter model on Z d \ Δ, while the process is conditioned to have only individuals carrying the transgene on Δ. Our main findings suggest that unless transgenes confer increased fitness in wild relatives, introgression of transgenes into populations of wild plants is slow and may even be reversible without intervention. Our study also addresses the effects of different spatial planting patterns of transgenic crops on the rate of introgression.

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Gene flow from imidazolinone-resistant domesticated sunflower to wild relatives

Weed Science ◽

10.1614/ws-03-032r ◽

2003 ◽

Vol 51 (6) ◽

pp. 854-862 ◽

Cited By ~ 48

Author(s):

Rafael A. Massinga ◽

Kassim Al-Khatib ◽

Paul St. Amand ◽

Jerry F. Miller

Keyword(s):

Gene Flow ◽

Wild Species ◽

Field Studies ◽

Wild Relatives ◽

Natural Conditions ◽

Resistant Gene ◽

Concentric Circles ◽

Moderately Resistant ◽

Resistant Progeny ◽

Domesticated Sunflower

Gene flow from imidazolinone (IMI)-resistant domestic sunflower to IMI-susceptible common sunflower and prairie sunflower was studied. Under greenhouse conditions, pollen from IMI-resistant domesticated sunflower was applied to flower heads of IMI-susceptible common and prairie sunflower. In addition, field studies were conducted in 2000 and 2001 near Manhattan, KS, to evaluate IMI-resistant gene flow from IMI-resistant domesticated sunflower to common and prairie sunflower under natural conditions. Common and prairie sunflower were planted in concentric circles at distances of 2.5, 5, 15, and 30 m around a densely planted IMI-resistant domesticated sunflower species. For both greenhouse and field studies, IMI-resistant gene flow was determined by treating the progeny of both wild species with 40 g ai ha−1of imazamox. Greenhouse crosses made by hand showed that 94% of common sunflower and 79% of prairie sunflower were resistant or moderately resistant. The resistant plants were allowed to grow in the greenhouse and were backcrossed with the corresponding susceptible wild parents. Progeny of the backcross showed a 1:1 ratio of resistant to susceptible plants. In the field, gene flow was detected up to 30 m from the pollen source for both species, and it decreased as distance from the pollen source increased. In 2000, 11 to 22% of the progeny were resistant at 2.5 m from the pollen source and 0.3 to 5% were resistant at 30 m. In 2001, the number of resistant progeny did not exceed 7 and 2% at 2.5 and 30 m from the pollen source, respectively. The results of this study showed that IMI-resistant domesticated sunflower outcrosses with common and prairie sunflower over distances typically encountered near production fields. Also, backcrosses of resistant hybrids with wild parents are successful, further increasing the potential for the spread of IMI-resistant feral sunflowers.

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Spontaneous gene flow from rapeseed ( Brassica napus ) to wild Brassica oleracea

Proceedings of The Royal Society B Biological Sciences ◽

10.1098/rspb.2006.3686 ◽

2006 ◽

Vol 273 (1605) ◽

pp. 3111-3115 ◽

Cited By ~ 30

Author(s):

Caroline S Ford ◽

Joël Allainguillaume ◽

Phil Grilli-Chantler ◽

Giulia Cuccato ◽

Charlotte J Allender ◽

...

Keyword(s):

Flow Cytometry ◽

Gene Flow ◽

Brassica Napus ◽

Microsatellite Markers ◽

Brassica Oleracea ◽

Brassica Rapa ◽

Environmental Risks ◽

Wild Relatives ◽

Similar Species ◽

In The Wild

Research on the environmental risks of gene flow from genetically modified (GM) crops to wild relatives has traditionally emphasized recipients yielding most hybrids. For GM rapeseed ( Brassica napus ), interest has centred on the ‘frequently hybridizing’ Brassica rapa over relatives such as Brassica oleracea , where spontaneous hybrids are unreported in the wild. In two sites, where rapeseed and wild B. oleracea grow together, we used flow cytometry and crop-specific microsatellite markers to identify one triploid F 1 hybrid, together with nine diploid and two near triploid introgressants. Given the newly discovered capacity for spontaneous introgression into B. oleracea , we then surveyed associated flora and fauna to evaluate the capacity of both recipients to harm cohabitant species with acknowledged conservational importance. Only B. oleracea occupies rich communities containing species afforded legislative protection; these include one rare micromoth species that feeds on B. oleracea and warrants further assessment. We conclude that increased attention should now focus on B. oleracea and similar species that yield few crop-hybrids, but possess scope to affect rare or endangered associates.

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A Bayesian analysis of gene flow from crops to their wild relatives: cultivated (Lactuca sativaL.) and prickly lettuce (L. serriolaL.) and the recent expansion ofL. serriolain Europe

Molecular Ecology ◽

10.1111/j.1365-294x.2012.05489.x ◽

2012 ◽

Vol 21 (11) ◽

pp. 2640-2654 ◽

Cited By ~ 21

Author(s):

BRIGITTE UWIMANA ◽

LUIGI D’ANDREA ◽

FRANÇOIS FELBER ◽

DANNY A. P. HOOFTMAN ◽

HANS C. M. Den NIJS ◽

...

Keyword(s):

Gene Flow ◽

Bayesian Analysis ◽

Wild Relatives ◽

Prickly Lettuce

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Voter Model and Biased Voter Model in Heterogeneous Environments

Journal of Applied Probability ◽

10.1239/jap/1189717544 ◽

2007 ◽

Vol 44 (3) ◽

pp. 770-787 ◽

Cited By ~ 1

Author(s):

N. Lanchier ◽

C. Neuhauser

Keyword(s):

Gene Flow ◽

Pollen Dispersal ◽

Transgenic Crops ◽

Wild Relatives ◽

Voter Model ◽

Wild Plants ◽

Transgenic Crop ◽

Heterogeneous Environments ◽

Wild Type ◽

Type Gene

With the rapid adoption of transgenic crops, gene flow from transgenic crops to wild relatives through pollen dispersal is of significant concern and warrants both empirical and theoretical studies to assess the risk of introduction of transgenes into wild populations. We propose to use the (biased) voter model in a heterogeneous environment to investigate the effects of recurrent gene flow from transgenic crop to wild relatives. The model is defined on the d-dimensional integer lattice that is divided into two parts, Δ and Zd \ Δ. Individuals carrying the transgene and individuals carrying the wild type gene compete according to the evolution rules of a (biased) voter model on Zd \ Δ, while the process is conditioned to have only individuals carrying the transgene on Δ. Our main findings suggest that unless transgenes confer increased fitness in wild relatives, introgression of transgenes into populations of wild plants is slow and may even be reversible without intervention. Our study also addresses the effects of different spatial planting patterns of transgenic crops on the rate of introgression.

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Gene Flow from Herbicide-Resistant Crops to Wild Relatives

Herbicide Resistance in Weeds and Crops ◽

10.5772/67645 ◽

2017 ◽

Cited By ~ 1

Author(s):

Sava Vrbničanin ◽

Dragana Božić ◽

Danijela Pavlović

Keyword(s):

Gene Flow ◽

Wild Relatives ◽

Herbicide Resistant

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Discordant Patterns of Introgression Suggest Historical Gene Flow into Thai Weedy Rice from Domesticated and Wild Relatives

Journal of Heredity ◽

10.1093/jhered/esz030 ◽

2019 ◽

Vol 110 (5) ◽

pp. 601-609 ◽

Cited By ~ 2

Author(s):

Marshall J Wedger ◽

Tonapha Pusadee ◽

Anupong Wongtamee ◽

Kenneth M Olsen

Keyword(s):

Gene Flow ◽

Ssr Markers ◽

Wild Rice ◽

Allelic Variation ◽

Wild Relatives ◽

Weedy Rice ◽

Cultivated Rice ◽

Crop Species ◽

Global Food Security ◽

North East

Abstract Weedy relatives of crop species infest agricultural fields worldwide, reducing harvests and threatening global food security. These weeds can potentially evolve and adapt through gene flow from both domesticated crop varieties and reproductively compatible wild relatives. We studied populations of weedy rice in Thailand to investigate the role of introgression from cultivated and wild rice in their evolution. We examined 2 complementary sources of genetic data: allelic variation at 3 rice domestication genes (Bh4, controlling hull color; Rc, controlling pericarp color and seed dormancy; and sh4, controlling seed shattering), and 12 previously published SSR markers. Sampling spanned 3 major rice growing regions in Thailand (Lower North, North East, and Central Plain) and included 124 cultivated rice accessions, 166 weedy rice accessions, and 98 wild rice accessions. Weedy rice strains were overall closely related to the cultivated varieties with which they co-occur. Domestication gene data revealed potential adaptive introgression of sh4 shattering alleles from wild rice. Introgression of potentially maladaptive rc crop alleles (conferring reduced dormancy) was also detected, with the frequency of the crop allele highest in northern populations. Although SSR markers also indicated introgression into weed populations from wild and cultivated rice, there was little overlap with domestication genes in the accessions showing admixed ancestry. This suggests that much of the introgression we detected at domestication genes most likely reflects past introgression rather than recent gene flow. This finding has implications for understanding long-term gene flow dynamics between rice and its weedy and wild relatives, including potential risks of transgene escape.

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