Phylogeny, Floral Evolution, and Inter-Island Dispersal in Hawaiian Clermontia (Campanulaceae) Based on ISSR Variation and Plastid Spacer Sequences

Abstract

Previous studies based on DNA restriction-site and sequence variation have shown that the Hawaiian lobeliads are monophyletic and that the two largest genera, Cyanea and Clermontia, diverged from each other ca. 9.7 Mya. Sequence divergence among species of Clermontia is quite limited, however, and extensive hybridization is suspected, which has interfered with production of a well-resolved molecular phylogeny for the genus. Clermontia is of considerable interest because several species posses petal-like sepals, raising the question of whether such a homeotic mutation has arisen once or several times. In addition, morphological and molecular studies have implied different patterns of inter-island dispersal within the genus. Here we use nuclear ISSRs (inter-simple sequence repeat polymorphisms) and five plastid non-coding sequences to derive biparental and maternal phylogenies for Clermontia. Our findings imply that (1) Clermontia is not monophyletic, with Cl. pyrularia nested within Cyanea and apparently an intergeneric hybrid; (2) the earliest divergent clades within Clermontia are native to Kauài, then Òahu, then Maui, supporting the progression rule of dispersal down the chain toward progressively younger islands, although that rule is violated in later-evolving taxa in the ISSR tree; (3) almost no sequence divergence among several Clermontia species in 4.5 kb of rapidly evolving plastid DNA; (4) several apparent cases of hybridization/introgression or incomplete lineage sorting (i.e., Cl. oblongifolia, peleana, persicifolia, pyrularia, samuelii, tuberculata), based on extensive conflict between the ISSR and plastid phylogenies; and (5) two origins and two losses of petaloid sepals, or—perhaps more plausibly—a single origin and two losses of this homeotic mutation, with its introgression into Cl. persicifolia. Our phylogenies are better resolved and geographically more informative than others based on ITS and 5S-NTS sequences and nuclear SNPs, but agree with them in supporting Clermontia's origin on Kauài or some older island and dispersal down the chain subsequently.

The quest to resolve recent radiations: Plastid phylogenomics of extinct and endangered Hawaiian endemic mints (Lamiaceae)

“…Phylogenies of the Hawaiian mints have been reconstructed from datasets composed of commonly used DNA sequence markers, including cpDNA and nuclear ribosomal 5S non-transcribed spacer and external transcribed spacer regions (Lindqvist and Albert, 2002;Roy et al, 2013), which are rapidly evolving in many other species (Baldwin and Markos, 1998;Shaw et al, 2005;Small et al, 1998), but they fail to resolve relationships among the Hawaiian mints. A similar pattern of low genetic diversity has been noted in other recent radiations of Hawaiian plants (Appelhans et al, 2014;Baldwin and Sanderson, 1998;Cronk et al, 2005;Givnish et al, 2009;Givnish et al, 2013). Given this low diversity in recent radiations, large amounts of data are clearly required to increase resolution.…”

“…The isolation of these islands (both from the mainland and from one another), plus the wealth of different habitats available, provides ideal settings for rapid diversification and adaptation (Emerson, 2002). The Hawaiian archipelago, which lies greater than 3700 km from the nearest continental landmass, provides several famous examples of organismal radiations, including Drosophila (Kambysellis et al, 1995), spiders (Gillespie et al, 1994), birds (Lerner et al, 2011), and plants, such as the silversword alliance (Witter and Carr, 1988), and lobelioids (Givnish et al, 2013).…”

Multiplexed‐shotgun‐genotyping data resolve phylogeny within a very recently derived insular lineage

“…Tolpis -There is little doubt that both inter-island dispersal (island hopping) and "adaptive" radiation on a single island play important roles in the diversifi cation of insular fl owering plants (e.g., Francisco-Ortega et al, 1997 ;Mort et al, 2002 ;Goodson et al, 2006 ;Givnish et al, 2013 ;Morden and Harbin, 2013 ;Talavera et al, 2013 ;Jones et al, 2014 ). On the Canary Islands, the emerging pattern of evolution for most endemic lineages is colonization via a single founder event, followed by diversifi cation, mostly through inter-island dispersal, but with infrequent withinisland radiations ( Mort et al, 2002 ;Talavera et al, 2013 ;Jones et al, 2014 ).…”

Genetic and Chemical Diversity in Perovskia abrotanoides Kar. (Lamiaceae) Populations Based on ISSRs Markers and Essential Oils Profile

“…Molecular markers provide a powerful tool for proper characterization of germplasm and chemotypes and their management. Among developed genetic markers, inter‐simple sequence repeat (ISSR) markers have been widely used for plant diversity analyses based on DNA finger‐printing, genetic diversity, population genetic, and phylogenetic studies . According to the literature information, ISSR markers have been efficiently used for the genetic analysis of several medicinal plant species …”