Dispersal of transgenes through maize seed systems in Mexico.
OBJECTIVE
Current models of transgene dispersal focus on gene flow via pollen while neglecting seed, a vital vehicle for gene flow in centers of crop origin and diversity. We analyze the dispersal of maize transgenes via seeds in Mexico, the crop's cradle.


METHODS
We use immunoassays (ELISA) to screen for the activity of recombinant proteins in a nationwide sample of farmer seed stocks. We estimate critical parameters of seed population dynamics using household survey data and combine these estimates with analytical results to examine presumed sources and mechanisms of dispersal.


RESULTS
Recombinant proteins Cry1Ab/Ac and CP4/EPSPS were found in 3.1% and 1.8% of samples, respectively. They are most abundant in southeast Mexico but also present in the west-central region. Diffusion of seed and grain imported from the United States might explain the frequency and distribution of transgenes in west-central Mexico but not in the southeast.


CONCLUSIONS
Understanding the potential for transgene survival and dispersal should help design methods to regulate the diffusion of germplasm into local seed stocks. Further research is needed on the interactions between formal and informal seed systems and grain markets in centers of crop origin and diversification.
Dyer
George A
GA
Department of Agricultural and Resource Economics, University of California Davis, Davis, California, United States of America. gdyer@primal.ucdavis.edu
Serratos-Hernández
J Antonio
JA
Perales
Hugo R
HR
Gepts
Paul
P
Piñeyro-Nelson
Alma
A
Chávez
Angeles
A
Salinas-Arreortua
Noé
N
Yúnez-Naude
Antonio
A
Taylor
J Edward
JE
Alvarez-Buylla
Elena R
ER
D000531:Altitude; D004058:Diffusion; D005843:Geography; D008800:Mexico; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D030821:Plants, Genetically Modified; D011157:Population Dynamics; D012639:Seeds / Q000235:genetics*; D019076:Transgenes / Q000235:genetics*; D003313:Zea mays / Q000235:genetics*
D010940:Plant Proteins