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Abstract
In the Pacific Northwest, there are discontinuities in the lineages of several plant and animal species in the northern California/Oregon region that are thought to have their origins in the separation of populations into refugia during the Pleistocene glacial periods. Redwood sorrel (
Oxalis oregana Nutt.), a common understory species of the California redwood forests and other Pacific Northwest temperate rainforests, was found to have two distinct genetic lineages in California based on sequence analysis of two chloroplast intergenic loci (
psbJ-petA and
trnQ-5’rps16) and the nuclear rDNA internal transcribed spacer (ITS) region. A "southern" lineage was detected in five populations from Big Sur to southern Humboldt County, and a "northern" lineage was dominant in two populations in northern Humboldt County and Del Norte County. The southern individuals had mixed sequence chloroplast haplotypes (presumably due to locus duplication and divergence or from chimeric tissue) while the vast majority of northern individuals had single sequence haplotypes. The northern and southern ITS variants were markedly divergent from each other, indicating a long period of separation between the lineages. Hybridization is occurring, as evidenced by an individual in a northern population that possesses a hybrid ITS genotype. The data suggest that these two groups were derived from an ancestral form that separated into two glacial refugia: a northern refugium within, or north of, the Klamath-Siskiyou ecoregion and a southern refugium in the California coastal forests.
Parent Publication
Citation
Brinegar, Chris. 2017. Two California lineages of
Oxalis oregana: genetic evidence for a Pleistocene separation into northern and southern glacial refugia. In: Standiford, Richard B.; Valachovic, Yana, tech cords. Coast redwood science symposium—2016: Past successes and future direction. Proceedings of a workshop. Gen. Tech. Rep. PSW-GTR-258. Albany, CA: U.S. Department of Agriculture, Forest Service, Pacific Southwest Research Station: 307-317.
