Chloroplast-DNA Variation in Tellima grandiflora (Saxifragaceae)

Abstract

Tellima grandiflora, a herbaceous, diploid (2n = 14) perennial, is distributed from the peninsula and panhandle of Alaska to central California. Restriction site variation of chloroplast DNA was surveyed in 51 populations representing the geographic range of T. grandiflora using 20 endonucleases. Two well‐differentiated clades of populations differing by 19 restriction site mutations and several length mutations are geographically structured. A northern group comprises populations from Alaska to central Oregon; populations from central Oregon to San Francisco, California, form a southern group. The southern lineage of the monotypic Tellima appears to have obtained its chloroplast genome via ancient hybridization with a species of Mitella. Although northern and southern lineages have well‐differentiated chloroplast genomes, populations of T. grandiflora show a high degree of genetic similarity of nuclear‐encoded allozymes; furthermore, no apparent morphological differences characterize the lineages. Significantly, several populations of T. grandiflora that possess the typical southern chloroplast genome also occur disjunctly on Prince of Wales Island, Alaska, and the Olympic Peninsula, Washington. Because both areas are proposed glacial refugia, we suggest that past glaciation may have created discontinuities in the geographic distribution of T. grandiflora. Following glaciation, migration of once‐isolated populations possessing different chloroplast genomes resulted in the formation of a continuous geographic distribution with a major organellar discontinuity. Additional support for this hypothesis is provided by the presence of well‐differentiated northern and southern chloroplast DNA lineages in Tolmiea menziesii, a species having a geographic distribution and life history traits similar to those of Tellima.

Divergence in the chloroplast genome and nuclear rDNA of the rare Western Australian plantLambertia orbifoliaGardner (Proteaceae)

“…This is similar to other plants where the majority of the mutations occur in the single‐copy regions, mainly the large single‐copy region, rather than the inverted repeat which is more conserved (Palmer et al . 1985; Sytsma & Gottlieb 1986; Soltis et al . 1991; Byrne & Moran 1994; Butcher et al .…”

Phylogeographical patterns in chloroplast DNA variation within the Acacia acuminata (Leguminosae: Mimosoideae) complex in Western Australia

“…Introgression of chloroplast lineages where hybridization was not suspected has been observed in a number of species, e.g. Tellima grandiflora (Soltis et al ., 1991), Populus nigra (Smith & Sytsma, 1990), Salix melanopsis (see Reiseberg & Brunsfeld, 1992). Introgression from another species is unlikely in A. acuminata as the two lineages coalesce to a common ancestor.…”

Geographic analysis of nucleotide diversity and song sparrow (Aves: Emberizidae) population history

“…Other authors have identified one or both of these regions as potential refugial sites in both animals and plants (e.g. Bernatchez & Dodson 1991; Soltis et al 1991; Hayes & Harrison 1992; O’Reilly et al 1993; Orti et al 1994; Talbot & Shields 1996). Southern California provides another potential refugial site, although more extensive sampling is needed to support this.…”