DNA Microsatellite Variation in the Coyote Ceanothus (Ceanothus ferrisiae)
Mentor:Rodney Honeycutt, Chairperson of the Natural Science Division, Pepperdine University
Ceanothus ferrisiae, a member of the California chaparral, is adapted to serpentine soils, thus creating a patchy distribution for the remaining populations. As such, the species represents one of the ten endangered species of plants in California. With a total population of approximately 6000 individuals, the Coyote Ceanothus continues to be threatened by anthropogenic processes. The required seismic retrofitting of the Anderson Dam Seismic Retrofit Project in Morgan Hill, Santa Clara County, California, represents a recent anthropogenic activity in a location containing some of the highest numbers of Coyote Ceanothus. As part of a species recovery plan, a population genetic study of the remaining populations of this species was initiated in an effort to identify existing populations genetically compatible with the Anderson Dam site. A panel of nuclear DNA microsatellite loci was used to estimate within and between population patterns of genetic diversity associated with the six remaining populations of Coyote Ceanothus. All analyses identified three genetically distinct populations of Coyote Ceanothus, one of which included four localities at or adjacent to the Anderson Dam. In general, estimates of between population divergences were higher for the three groups of Coyote Ceanothus than seen for comparisons between island and mainland populations of Ceanothus megacarpus. In addition, overall levels of heterozygosity and number of alleles per locus were considerably lower than seen for other species of Ceanothus. Collectively, these data suggest high degree of genetic isolation among the three main groups of Coyote Ceanothus, possibly revealing the degree to which habitat structure has influenced patterns of gene flow between isolated populations confined to serpentine soils. These findings also have management implications for the establishment of a restoration plan for populations adjacent to the Anderson Dam, and for the ones at Llagas Road and Kirby Canyon.