Plant & Animal Genome VI Conference

P85

GENE FLOW BETWEEN WILD AND CULTIVATED Phaseolus vulgaris L. IN MEXICO: POTENTIAL FOR GENE ESCAPE FROM TRANSGENIC PLANTS INTO WILD POPULATION?

1. Dipartimento di Biotecnologie Agrarie ed Ambientali, Università degli Studi di Ancona, Via Brecce Bianche, 60131 ANCONA, ITALY
2. INIFAP-CEVAMEX, Km. 38.5 Carr. México-Texcoco, Apdo. Postal 10, CP56230 CHAPINGO, Méx., MEXICO,
3. UNAM, Instituto de Biologia, Apdo. Postal 70-233, CP 04510 MEXICO, DF, MEXICO
4. Dept. of Agronomy and Range Science, University of California, One Shields Ave., Davis, CA 95616-8515, USA

A study was conducted of gene flow between wild and cultivated of the predominantly self-pollinating species Phaseolus vulgaris L., Fabaceae (2n=2x=22) in Mexico in order to assess the potential risk connected to gene escape from transgenic plants into wild populations. Two different experiments were conducted using AFLP markers, the first studying 70 genotypes of wild and cultivated common bean from Mexico, the second on 24 populations of wild and cultivated common bean collected on asingle plant basis at different levels of sympatry. The evaluation of gene flow was based on the population structure analysis. The results obtained show that, in general, gene flow between wild and cultivated common bean populations is an event that occurs rarely, as could be expected in the presence of a low outcrossing rate and with divergent selection between the wild and domesticated environments. Only in a few, local cases did gene flow seem to be an important phenomenon. In these cases, it appeared to be an asymmetrical event with geen flow predominantly from cultivated to wild beans. According to our results, gene escape from transgenic plants does not seem to be a major risk, at least if the transgenes do not confer a strong selective advantage in the wild environments. There is a need to increase our knowledge of the ecological factors influencing gene flow.