Individual plants of several Amelanchier taxa contain many polymorphic nucleotide sites in the internal transcribed spacers (ITS) of nuclear ribosomal DNA (nrDNA). This polymorphism is unusual because it is not recent in origin and thus has resisted homogenization by concerted evolution. Amelanchier ITS sequence polymorphism is hypothesized to be the result of gene flow between two major North ...

Dolichopus humilis Van Duzee, 1921 was described from the Alaska-Yukon Territory boundary (Van Duzee et al. 1921), and later recorded from Alaska, Northwest Territories and Greenland (J.R. Vockeroth in Pollet et al. 2004). This species was redescribed and illustrated by Pollet and Böcher (2005). It was never associated with the Dolichopus latipennis species group (= Hygroceleuthus Loew, 1857). ...

One of the desiccation-tolerant mechanisms of the resurrection plant, Xerophyta humilis, is the ability to shut down photosynthesis reversibly. The X. humilis psbR and ChlP genes, encoding the 10 kDa polypeptide of photosystem II (PSII) and a geranylgeranyl reductase, respectively, were isolated in a differential display screen as dehydration-down-regulated and rehydration-up-regulated transcri...

The effects of Pleistocene glaciations and geographical barriers on the phylogeographic patterns of lowland plant species in Mediterranean-climate areas of Central Chile are poorly understood. We used Dioscorea humilis (Dioscoreaceae), a dioecious geophyte extending 530 km from the Valparaíso to the Bío-Bío Regions, as a case study to disentangle the spatio-temporal evolution of populations in ...

The dwarf marmoset, described as Callithrix humilis by van Roosmalen et al. (1998), is an anomaly among Amazonian marmosets for its size, morphology and behavior. We compare cranial and mandibular characters of the dwarf marmoset with representatives of four other callitrichid genera. C. humilis displays qualitative differences in skull morphology when compared to other callitrichids, and a dis...

Pinus edulis and Juniperus monosperma seedlings were inoculated separately with each of seven nematode species, and grown for 9 months at 20 C soil temperature. Hoplolaimus galeatus, Rotylenchus pumilis, Tylenchus exiguus, and Xiphinema americanum parasitized P. edulis seedlings, but did not significantly reduce seedling growth. Pinus edulis was not a host for Tylenchorhynchus cylindricus, Aphe...

The annotation of novel plant genes is frequently based on sequence and structural similarity to known protein motifs. Understanding the biological function of these genes is dependent on identifying conditions under which they are activated, however. The resurrection plant, Xerophyta humilis is a good model system for identifying and characterizing genes which are important for desiccation tol...

Life history characteristics play a pervasive role in the ecology and evolution of species. Transitions between feeding and non-feeding larval development have occurred many times in both terrestrial and marine phyla, however we lack a comprehensive understanding of how such shifts occur. The sea biscuits Clypeaster rosaceus and Clypeaster subdepressus employ different life history strategies (...