Evolutionary ecology of the prezygotic stage

The life cycles of sexually reproducing animals and flowering plants begin with male and female gametes and their fusion to form a zygote. Selection at this earliest stage is crucial for offspring quality and raises similar evolutionary issues, yet zoology and botany use dissimilar approaches. There are striking parallels in the role of prezygotic competition for sexual selection on males, cryptic female choice, sexual conflict, and against selfish genetic elements and genetic incompatibility. In both groups, understanding the evolution of sex-specific and reproductive traits will require an appreciation of the effects of prezygotic competition on fitness.

Gene dispersal from transgenic potatoes to conspecifics: a field trial

Transgenic potatoes containing the marker genes NTP II and GUS were planted in the field and at varying distances (0-1, 1-2, 2-3, 10, 100 and 11000 m) from them were patches of untransformed potatoes of another variety. All seeds produced by the untransformed potatoes were collected after the flowering season and screened for the presence of the marker genes. Gene dispersal was found to be highest in the immediate vicinity (72%). At the consecutive distances the presence of the gene was more or less constant (35%). Thus gene dispersal occurred both over large distances and to a higher extent than has been previously shown. Pollinator availability, as well as the foraging behaviour of the pollinators, are suggested to be important in this study. The plant material used is discussed in the light of sexually selected traits which could have contributed to the high gene dispersal.