Impact of Transgene Inheritance on the Mitigation of Gene Flow Between Crops and Their Wild Relatives: The Example of Foxtail Millet

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.

Download Full-text

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.

Download Full-text

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.

Download Full-text

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

Download Full-text

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.

Download Full-text