Environmental complexity and biodiversity: the multi-layered evolutionary history of a log-dwelling velvet worm in Montane Temperate Australia.

Phylogeographic studies provide a framework for understanding the importance of intrinsic versus extrinsic factors in shaping patterns of biodiversity through identifying past and present microevolutionary processes that contributed to lineage divergence. Here we investigate population structure and diversity of the Onychophoran (velvet worm) Euperipatoides rowelli in southeastern Australian montane forests that were not subject to Pleistocene glaciations, and thus likely retained more forest cover than systems under glaciation. Over a ~100 km transect of structurally-connected forest, we found marked nuclear and mitochondrial (mt) DNA genetic structuring, with spatially-localised groups.

An enhanced miniaturized assay for antimicrobial prospecting.

Bioprospecting for novel antimicrobials increasingly relies on extremely small samples unsuitable for conventional bulk extraction and assay. We developed a microtitre plate assay for minimal amounts of test materials which is rapid, extremely sensitive, allows time-course analysis and reduces false negatives. Developed for the analyses of antimicrobial sensitivity and resistance, the technique is appropriate for assays where source materials are scarce.

Fine-scale genetic structure and fire-created habitat patchiness in the Australian allodapine bee, Exoneura nigrescens (Hymenoptera: Apidae).

Fire promotes an abundance of nest sites for the stem nesting bee Exoneura nigrescens, which remain viable for approximately 10 years. The finite duration of nesting substrate and localized fire events suggest that migration should minimize genetic structure among suitable habitat patches. Exoneura nigrescens was sampled from 7 localities with a known fire history in southwestern Victoria, Australia.

Widespread utility of highly informative AFLP molecular markers across divergent shark species.

Population numbers of many shark species are declining rapidly around the world. Despite the commercial and conservation significance, little is known on even the most fundamental aspects of their population biology. Data collection that relies on direct observation can be logistically challenging with sharks.

Comparative losses of quantitative and molecular genetic variation in finite populations of Drosophila melanogaster.

Quantitative genetic variation, the main determinant of the ability to evolve, is expected to be lost in small populations, but there are limited data on the effect, and controversy as to whether it is similar to that for near neutral molecular variation. Genetic variation for abdominal and sternopleural bristle numbers and allozyme heterozygosity were estimated in 23 populations of Drosophila melanogaster maintained at effective population sizes of 25, 50, 100, 250 or 500 for 50 generations, as well as in 19 highly inbred populations and the wild outbred base population. Highly significant negative regressions of proportion of initial genetic variation retained on inbreeding due to finite population size were observed for both quantitative characters (b = -0.

Fitness and adaptation in a novel environment: effect of inbreeding, prior environment, and lineage.

The ability of populations to undergo adaptive evolution depends on the presence of genetic variation for ecologically important traits. The maintenance of genetic variation may be influenced by many variables, particularly long-term effective population size and the strength and form of selection. The roles of these factors are controversial and there is very little information on their impacts for quantitative characters.

A rapid fish radiation associated with the last sea-level changes in southern Brazil: the silverside Odontesthes perugiae complex.

Coastal freshwater fishes provide valuable models for studying the role of the last glaciations in promoting speciation. To date, the great majority of studies are of Northern Hemisphere taxa, and reflect the influence of vicariant events during, or prior to, the Pleistocene. Microsatellite markers and mitochondrial DNA sequences were used to investigate patterns of population divergence and evolutionary relationships in a freshwater group of silverside fishes (Odontesthes perugiae complex), endemic to the recently formed coastal plain of southern Brazil.

Correlation of Histocompatibility Reactions with Fusion Between Conspecifics in the Solitary Urochordate Styela plicata.

Previous transplantation analysis has identified a sensitive histocompatibility system in the solitary urochordate Styela plicata that obeys genetic transplantation "rules" identical to those of vertebrates. The current study demonstrates that histocompatibility acts to prevent fusion between conspecifics in sedentary aggregations of this species. Pairs of naturally fused individuals were present at low frequencies (0.