PHYLOGENETICS OF THE LISIANTHIUS SKINNERI (GENTIANACEAE) SPECIES COMPLEX IN PANAMA UTILIZING DNA RESTRICTION FRAGMENT ANALYSIS

Abstract

Abstract.-The well-delimited and evolutionary interesting tropical shrub group, the Lisianthius skinneri (Gentianaceae) species complex, was analyzed for variation in nuclear ribosomal DNA and chloroplast DNA by restriction endonuclease fragment analysis. A most parsimonious tree using variations in both DNAs was constructed for seven populations in the group by including an appropriate outgroup, This phylogeny is significantly more compatible with the DNA data than most, but not all, less parsimonious phylogenies. At least two distinct lineages have independently evolved geographically restricted, cloud forest species from the putative ancestral, widespread, and lower elevation L. skinneri. Lisianthius skinneri itselfis shown to be paraphyletic with populations derived separately from the two distinct lineages. Except for a switch in the placement of two populations, this DNA-based phylogeny is congruent with an isozyme-based Wagner network depicting relationships in the species complex. Relative rates of divergence, in terms of nuclear ribosomal DNA, chloroplast DNA, isozymes, and morphology, differ markedly within and between lineages. The non-transcribed spacer region of ribosomal DNA is shown to evolve in a manner that is not in accord with a molecular clock hypothesis. Small population sizes, restricted and isolated nature of populations, and probable founder events are suggested as instrumental in causing this lack of concerted divergence within and between lineages of the L. skinneri species complex.

More Characters or More Taxa for a Robust Phylogeny—Case Study from the Coffee Family (Rubiaceae)

“…Plant molecular systematics began with restriction site mapping of chloroplast DNAs (e.g., Sytsma and Schaal, 1985;Jansen and Palmer, 1987;Palmer, 1989, Wilson et al, 1990). Although the restriction site approach still provides very valuable phylogenetic information, especially at lower taxonomic levels, there are some limitations of the approach (reviewed in Jansen et al, 1998).…”

Phylogenetic Relationships in the Subfamily Bovinae (Mammalia: Artiodactyla) Based on Ribosomal DNA

“…Numerous Robertsonian events have occurred during the radiation of the group, particularly in the buffaloes. Phylogenies based on ribosomal DNA, morphology, and chromosomes are combined to give a hypothesis of evolution in the subfamily.Several recent studies have used restriction-site mapping of the nuclear-ribosomal DNA regions as a tool for phylogenetic analysis (Hillis and Davis, 1986;Sites and Davis, 1989;Systma and Schaal, 1985). Ribosomal DNA consists of a series of tandemly repeated sequences that contain the 18s, 5.8s, and 28s genes and the spacer regions that surround them.…”

“…Several recent studies have used restriction-site mapping of the nuclear-ribosomal DNA regions as a tool for phylogenetic analysis (Hillis and Davis, 1986;Sites and Davis, 1989;Systma and Schaal, 1985). Ribosomal DNA consists of a series of tandemly repeated sequences that contain the 18s, 5.8s, and 28s genes and the spacer regions that surround them.…”

“…Probe was stripped from filters by incubating for 10 min in boiling 20X sodium chloride-sodium citrate (3 M sodium chloride, 0.3 M trisodium citrate; pH 7.0) before reuse. Hybridization and washing procedures were the same as those used by Systma and Schaal (1985). Autoradiographs were prepared by exposing the hybridized membranes to Kodak XAR-5 film in cassettes with intensifying screens for 15-36 h at -80°C.…”

Chloroplast DNA variability in the genus Helianthus: restriction analysis and S1 nuclease mapping of DNA-DNA heteroduplexes

“…Our data are not numerous enough to assess the phylogenetic relationships between these ecotypes; in addition, the majority of the mutations detected cannot be related with the classification of the species proposed by Schilling and Heiser [19]. They allow however a rough estimation of the [15]) or in Clarkia (0.2%-1.6%; [22]) and the low heterogeneity found in Lisianthus (0%-0.3%; [23]) or in Zea (0.03%-0.24%; [5]). …”