Comparisons between insular and continental radiations have been hindered by a lack of reliable estimates absolute diversification rates in island lineages. We took advantage rate-constant rDNA sequence evolution an "external" calibration using paleoclimatic fossil data to determine the maximum age minimum rate Hawaiian silversword alliance (Compositae), textbook example adaptive radiation plants. Our maximum-age estimate 5.2 +/- 0.8 million years ago for most recent common ancestor is much...

Individual plants of several Amelanchier taxa contain many polymorphic nucleotide sites in the internal transcribed spacers (ITS) nuclear ribosomal DNA (nrDNA). This polymorphism is unusual because it not recent origin and thus has resisted homogenization by concerted evolution. ITS sequence hypothesized to be result gene flow between two major North American clades resolved phylogenetic analysis sequences. Western species plus A. humilis sanguinea eastern America form one clade (A),...

Phylogenetic patterns within Calycadenia were estimated from 18–26S nuclear ribosomal DNA sequences of the internal transcribed spacer (ITS) region in 19 representatives all species , including Osmadenia ( C .) tenella and two outgroup species. In pairwise comparisons among sequences, divergence ranged 0 to 11.2% nucleotides ITS 1 8.6% 2. Of 62 nucleotide sites with potential phylogenetic information, 51.6% 1, 46.8% 2, 1.6% 5.8S subunit. A highly resolved, strict consensus tree Wagner...

The polyploid Hawaiian silversword alliance (Asteraceae), a spectacular example of adaptive radiation in plants, was shown previously to have descended from North American tarweeds the Madia/Raillardiopsis group, primarily diploid assemblage. origin condition not resolved earlier biosystematic, cytogenetic, and molecular studies, apart determination that polyploidy modern species arose independent group. We determined two floral homeotic genes, ASAP3/TM6 ASAP1, are found duplicate copies...

Evolutionary relationships within Astragalus L. (Fabaceae) were inferred from nucleotide sequence variation in nuclear ribosomal DNA of both New World and Old species. The internal transcribed spacer regions (ITS) 18S–26S representatives 26 species , three Oxytropis DC., two outgroup taxa analyzed by polymerase chain reaction amplification direct sequencing. length the ITS 1 region these varied 221 to 231 bp, while 2 207 217 bp. Of aligned, unambiguous positions, approximately 34% variable...

Results of the first genus-wide phylogenetic analysis for Santalum (Santalaceae), using a combination 18S-26S nuclear ribosomal (ITS, ETS) and chloroplast (3' trnK intron) DNA sequences, provide new perspectives on relationships biogeographic patterns among widespread economically important sandalwoods. Congruent trees based maximum parsimony, likelihood, Bayesian methods support an origin in Australia at least five putatively bird-mediated, long-distance dispersal events out Australia, with...

Chloroplast DNA restriction-site comparisons were made among 24 species of the Hawaiian silversword alliance (Argyroxiphium, Dubautia, and Wilkesia) 7 North American perennial tarweeds in Adenothamnus, Madia, Raillardella, Raillardiopsis (Asteraceae-Madiinae). These data results from intergeneric hybridization indicated surprisingly close genetic affinity monophyletic group to two diploid montane herbs California, Madia bolanderi muirii. Of 117 mutations shared a subset or more accessions,...

California is a world floristic biodiversity hotspot where the terms neo- and paleo-endemism were first applied. Using spatial phylogenetics, it now possible to evaluate from an evolutionary standpoint, including discovering significant areas of paleo-endemism, by combining information museum collections DNA-based phylogenies. Here we used distributional dataset 1.39 million herbarium specimens, phylogeny 1083 operational taxonomic units (OTUs) 9 genes, randomization test identify regions...

BackgroundPutative phytogeographical links between America (especially North America) and the Hawaiian Islands have figured prominently in disagreement debate about origin of Pacific floras efficacy long-distance (oversea) plant dispersal, given obstacles to explaining such major disjunctions by vicariance.

Recent biogeographic and evolutionary studies have led to improved understanding of the origins exceptionally high plant diversity in California Floristic Province (CA-FP). Spatial analyses Californian endemism reinforce importance geographically isolated areas topographic edaphic complexity as floristic hot spots, which relative influence factors promoting divergence buffering lineages against extinction has gained increased attention. Molecular phylogenetic spanning flora indicate that...

The Hawaiian silversword alliance (Asteraceae) is an iconic adaptive radiation. However, like many island plant lineages, no fossils have been assigned to the clade. As a result, clade's age and diversification rate are not known precisely, making it difficult test biogeographic hypotheses about In lieu of fossils, paleogeographically structured processes may inform species divergence times; for example, must first exist clade radiate upon it. We date its radiation across Archipelago by...

Species of Collinsia and Tonella, the two sister genera self-compatible annuals that constitute tribe Collinsieae, show extensive variation in floral size morphology patterns stamen style elongation during life flower (anthesis). We used a nuclear ribosomal ITS phylogeny, independent contrasts, phylogenetically corrected path analysis to explore covariance developmental morphological traits potentially influencing mating system. Large-flowered taxa maintain herkogamy (spatial separation...

Heterogeneous DNA substitution rates were found in the 18S-26S nuclear ribosomal internal transcribed spacer (ITS) and external (ETS) regions of Sidalcea (Malvaceae), a putatively young genus annuals perennials. The majority comparisons revealed that annual species had significantly higher molecular evolutionary than perennials, whereas consistently homogenous between obligate species. These findings led us to conclude generation time or possibly another biological factor distinguishing...

Abstract The apparent recency of diversification Californian Lessingia (Compositae, Astereae) makes the genus a particularly interesting group for evolutionary investigation. Here we focus on major lineages within (sensu Lane 1992) and higher-level relationships presumed close relatives using sequence data from 18S–26S nuclear ribosomal DNA (nrDNA) internal transcribed spacer (ITS) region 3’ end (561–563 bp) external (ETS). We present new 3‘ETS primers that are useful across Astereae examine...

Abstract The internal transcribed spacer (ITS) region of 18S–26S nuclear ribosomal DNA (rDNA) was sequenced in 65 taxa representing most coneflowers (i.e., species Dracopis, Echinacea, Ratibida, and Rudbeckia) other 21 outgroup genera tribe Heliantheae. Results parsimony analysis the rDNA dataset by itself combination with cpDNA uphold hypothesis from an earlier restriction site study that Echinacea is not closely related to three coneflowers. data support placement subtribe Zinniinae....

Abstract Results of phylogenetic analyses nuclear 18S–26S rDNA internal transcribed spacer (ITS) region sequences for representatives most genera helenioid Heliantheae and various members s.s. (sensu stricto) Eupatorieae help to clarify major lineages relationships in the clade corresponding s.l. lato) Eupatorieae. Most subtribes as circumscribed by Robinson (1981) correspond closely with ITS clades. Polygeneric that appear be monophyletic based on data include Flaveriinae sensu Turner...

Abstract Aim Sustaining biological diversity requires the protection of ecological, evolutionary and landscape‐level processes that generate it. Here, we identify areas high neoendemism in a global hotspot, California flora, using range size data molecular‐based estimates taxon age. Location California, USA. Methods We compiled distribution for all plant taxa endemic to internal transcribed spacer (ITS)‐based age 337 putative neoendemics (15% flora). This information was combined state with...