Thesis

Microsatellite Development in "Plantanus" for Documenting Gene Flow Among Species

ABSTRACT MICROSATELLITE DEVELOPMENT IN PLATANUS FOR DOCUMENTING GENE FLOW AMONG SPECIES by Kylene R. Lang Master of Science in Biological Sciences California State University, Chico Fall 2010 Hybridization is a primary source of invasive genotypes and has been shown to contribute to the loss of diversity in a number of locally adapted species. The focus of this study is to develop microsatellite markers with the intent to quantify gene flow within the ancient genus Platanus between the native taxa (P. racemosa, P. racemosa var. wrightii, P. occidentalis, and P. orientalis) and the ornamental P. x acerifolia. Platanus is wind-pollinated, and its species readily hybridize. The horticultural P. x acerifolia is widely planted for its tolerance to infection and other city stresses, and through hybridization events is endangering the genetic integrity of native Platanus populations in already compromised, shrinking riparian habitats. Thirteen of 28 developed microsatellite primer pairs amplified simple sequence repeat (SSR) loci for all Platanus taxa. Species specific alleles were discovered in P. racemosa (n = 18), P. occidentalis vii (n = 31), and P. orientalis (n = 13). Alleles otherwise found only in P. occidentalis and P. orientalis were also found in putative P. racemosa X P. x acerifolia hybrids. Genetic admixture was apparent upon analysis with STRUCTURE; notably putative P. racemosa X P. x acerifolia hybrids clustered primarily with P. racemosa, but also with P. occidentalis and P. orientalis. Genetic differentiation estimates (F’ST) ranged from 0.047 to 0.549 (omitting 1 monomorphic locus). These data will serve as the basis for a larger scale sampling efforts to predict the long-term consequences of gene movement out of P. x acerifolia and into their native congeners at the regional and landscape level.

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