Interrelationships of chromalveolates within a broadly sampled tree of photosynthetic protists.

The Chromalveolata "supergroup" is a massive assemblage of single-celled and multicellular protists such as ciliates and kelps that remains to be substantiated in molecular trees. Recent multigene analyses place chromalveolates into two major clades, the SAR (Stramenopiles, Alveolata, and Rhizaria) and the Cryptophyta+Haptophyta. Here we determined 69 new sequences from different chromalveolates to study the interrelationships of its constituent phyla.

Phylogenetic, morphological, and chemotaxonomic incongruence in the North American endemic genus Echinacea.

The study of recently formed species is important because it can help us to better understand organismal divergence and the speciation process. However, these species often present difficult challenges in the field of molecular phylogenetics because the processes that drive molecular divergence can lag behind phenotypic divergence. In the current study we show that species of the recently diverged North American endemic genus of purple coneflower, Echinacea, have low levels of molecular divergence.

Phylogenetic determination of the pace of transposable element proliferation in plants: copia and LINE-like elements in Gossypium.

Transposable elements contribute significantly to plant genome evolution in myriad ways, ranging from local insertional mutations to global effects exerted on genome size through accumulation. Differential accumulation and deletion of transposable elements may profoundly affect genome size, even among members of the same genus. One example is that of Gossypium (cotton), where much of the 3-fold genome size variation is due to differential accumulation of one gypsy-like LTR retrotransposon, Gorge3.