Learn More
Polar bears (PBs) are superbly adapted to the extreme Arctic environment and have become emblematic of the threat to biodiversity from global climate change. Their divergence from the lower-latitude brown bear provides a textbook example of rapid evolution of distinct phenotypes. However, limited mitochondrial and nuclear DNA evidence conflicts in the(More)
Seven species of polycystine radiolarians and one phaeodarian species were investigated in order to determine the diversity of their associate organisms and their species specificity. Twelve partial 18S ribosomal DNA (rDNA) sequences were obtained showing a high diversity of associates, both within spumellarian and nassellarian radiolarians and among(More)
The polar bear has become the flagship species in the climate-change discussion. However, little is known about how past climate impacted its evolution and persistence, given an extremely poor fossil record. Although it is undisputed from analyses of mitochondrial (mt) DNA that polar bears constitute a lineage within the genetic diversity of brown bears,(More)
The Hawaiian endemic mints constitute a major island radiation, displaying a remarkable diversity of floral, fruit, and vegetative features. Haplostachys and Phyllostegia have flowers associated with insect pollination, whereas Stenogyne has flowers typical of bird pollination. The three genera had been thought to be closely related to East Asian members of(More)
Polar bears (Ursus maritimus) face extremely cold temperatures and periods of fasting, which might result in more severe energetic challenges than those experienced by their sister species, the brown bear (U. arctos). We have examined the mitochondrial and nuclear genomes of polar and brown bears to investigate whether polar bears demonstrate(More)
The endemic Hawaiian mints represent a major island radiation that likely originated from hybridization between two North American polyploid lineages. In contrast with the extensive morphological and ecological diversity among taxa, ribosomal DNA sequence variation has been found to be remarkably low. In the past few years, expressed sequence tag (EST)(More)
Most angiosperm flowers are tightly integrated, functionally bisexual shoots that have carpels with enclosed ovules. Flowering plants evolved from within the gymnosperms, which lack this combination of innovations. Paradoxically, phylogenetic reconstructions suggest that the flowering plant lineage substantially pre-dates the evolution of flowers(More)
The rhizome ofActaea racemosa L., commonly called black cohosh, is a popular botanical dietary supplement used to treat female health concerns. The rhizomes used in black cohosh products are often collected from the wild. To ensure quality control, it is imperative that plants be correctly identified. This paper examines the use of the DNA fingerprinting(More)
A controversial topic in evolutionary developmental biology is whether morphological diversification in natural populations can be driven by expansions and contractions of amino acid repeats in proteins. To promote adaptation, selection on protein length variation must overcome deleterious effects of multiple correlated traits (pleiotropy). Thus far,(More)
Although tribe Stachydeae (Lamiaceae) is considered monophyletic, relationships within the tribe are still poorly understood. The complexity of Stachydeae includes paraphyletic genera, considerable morphological plasticity, a range of ploidy levels, and presumably frequent natural hybridization. We performed parsimony and Bayesian phylogenetic analyses of(More)