Are neopolyploids a likely route for a transgene walk to the wild? The Aegilops ovata × Triticum turgidum durum case

Spontaneous hybridization between durum wheat ( Triticum turgidum durum ) and Aegilops ovata is regularly observed in nature. The frequency of spontaneous amphiploidy in sympatric populations was estimated at 10⁻⁶ (direct in situ observations and germinated seed collected from A. ovata plants). In nursery conditions some genotype combinations gave frequencies that were much higher at 10⁻³. Genomic in situ hybridization revealed that fertile amphiploids had arisen through unreduced gametes, and that some of them carried wheat −  A. ovata recombinant chromosomes. The frequency of production of unreduced gametes is probably genetically inherited. Amphiploids provide a route for gene flow, including that of transgenes, to the wild. Gene flow could potentially be minimized through the choice of wheat cultivars that produce a low frequency of unreduced gametes.  © 2004 The Linnean Society of London, Biological Journal of the Linnean Society , 2004, 82 , 503–510.