SGER: Gene Flow and Hybridization Between Introduced and Endemic Populations of Three Native Perennial Grass Species

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0081024Mazer and ReichmanA fundamental problem in population biology is determining the extent of the spread of novel genes in natural populations and its effect on evolutionary and ecological processes. In plants, the introduction of novel genetic material into indigenous populations is becoming more common due to the accidental spread of seeds and due to attempts to restore native vegetation. While the introduction of new genetic material may benefit populations with little genetic diversity, there are also serious potential risks. For example, when individuals representing genetically distinct populations mate and hybridize, the mixing of the genetic material from the two populations through sexual reproduction can result in hybrid offspring (or grandoffspring, two generations later) that are poorly adapted to local ecological conditions. This phenomenon is known as "hybrid breakdown" and can result in an increased risk of extinction. To date, the possibility that major restoration efforts may hold such a "poison pill" for future generations (i.e., hybrid breakdown) has just begun to be discussed by ecologists. The collaboration to be initiated here will be the first study of this possibility in grassland species, which have been a major focus of restoration efforts. The investigators will use molecular fingerprinting techniques to seek evidence for hybridization and hybrid breakdown between introduced and resident populations of three species of native California perennial grasses at an extensive grassland/oak woodland reserve managed by the University of California.