First record of multiple paternity in the pygmy rabbit ( Brachylagus idahoensis ): evidence from analysis of 16 microsatellite loci

Although promiscuity is believed to be common among leporids, little is known about the mating system of free-ranging pygmy rabbits ( Brachylagus idahoensis ). We used 16 polymorphic microsatellite markers and DNA extracted from tissue samples of 10 rabbits from 2 litters collected in east central Idaho to evaluate paternity. We incorporated maternal genotypes for better resolution and employed an exclusion approach to detect multiple paternity. Our results demonstrated multiple paternity at 6 of the 16 loci tested for each litter. These findings support the expectation that pygmy rabbits have a promiscuous mating system. It has been proposed that multiple paternity could lead to higher effective population sizes and help small populations maintain diversity. Given that pygmy rabbits persist in small and fragmented populations, a promiscuous mating system might be important for maintaining genetic diversity in free-ranging populations and could be advantageous for the captive breeding program. Aunque se cree que la promiscuidad es común entre los lepóridos, se conoce poco sobre el sistema de apareamiento del conejo pigmeo ( Brachylagus idahoensis ) en condiciones silvestres. Utilizamos 16 marcadores de microsatélites polimórficos y ADN extraído de muestras de tejido de 10 conejos de 2 camadas colectadas en la parte este central de Idaho para evaluar su paternidad. Los genotipos maternos fueron incorporados para lograr una mayor resolución y empleamos un método de exclusión para detectar la paternidad múltiple. Nuestros resultados demuestran paternidad múltiple en 6 de los 16 loci examinados en cada camada. Estos resultados apoyan la suposición de que los conejos pigmeos tienen un sistema de apareamiento promiscuo. Se ha propuesto que la paternidad múltiple podría conducir a tamaños efectivos de la población más grandes y ayudar a que las poblaciones pequeñas mantengan la diversidad. En vista de que el conejo pigmeo persiste en poblaciones pequeñas y fragmentadas, un sistema de apareamiento promiscuo podría ser importante para mantener la diversidad genética en poblaciones silvestres y podría resultar provechoso para el programa de cría en cautiverio.     

Survey indicators for pygmy rabbits: temporal trends of burrow systems and pellets

Obtaining estimates of absolute abundance for rare or cryptic species can be challenging. In these cases,methods using indirect indicators such as sign might offer useful indices of population size. Pygmy rabbits ( Brachylagus idahoensis ) are small, burrowing lagomorphs for which methods for population assessment and monitoring are needed. Current tools for estimating relative abundance rely on detecting and assessing fecal pellets and burrow systems. We evaluated temporal changes in each of these indicators to gauge their potential usefulness as indicators of relative and absolute abundance of pygmy rabbits. Pellet persistence was strongly influenced by environmental exposure, and based on our data, we estimated that maximum persistence of fecal pellets would be 24–34 months. Pellet appearance (color) was affected by both time and exposure. Burrow systems were remarkably resilient over the course of the study. Probability of burrow systems transitioning between activity classes (active, recent, and old) did not vary detectably by study site, season, or year. We suggest that 2 protocols currently used for classification of pygmy rabbit burrow systems are most useful for different applications. Further work is needed, however, to link such assessments to quantitative estimates of population size.     

Metagenomic analysis of a permafrost microbial community reveals a rapid response to thaw

Permafrost contains an estimated 1672?Pg carbon (C), an amount roughly equivalent to the total currently contained within land plants and the atmosphere. This reservoir of C is vulnerable to decomposition as rising global temperatures cause the permafrost to thaw. During thaw, trapped organic matter may become more accessible for microbial degradation and result in greenhouse gas emissions. Despite recent advances in the use of molecular tools to study permafrost microbial communities, their response to thaw remains unclear. Here we use deep metagenomic sequencing to determine the impact of thaw on microbial phylogenetic and functional genes, and relate these data to measurements of methane emissions. Metagenomics, the direct sequencing of DNA from the environment, allows the examination of whole biochemical pathways and associated processes, as opposed to individual pieces of the metabolic puzzle. Our metagenome analyses reveal that during transition from a frozen to a thawed state there are rapid shifts in many microbial, phylogenetic and functional gene abundances and pathways. After one week of incubation at 5?°C, permafrost metagenomes converge to be more similar to each other than while they are frozen. We find that multiple genes involved in cycling of C and nitrogen shift rapidly during thaw. We also construct the first draft genome from a complex soil metagenome, which corresponds to a novel methanogen. Methane previously accumulated in permafrost is released during thaw and subsequently consumed by methanotrophic bacteria. Together these data point towards the importance of rapid cycling of methane and nitrogen in thawing permafrost.     

Domination of heliosheath pressure by shock-accelerated pickup ions from observations of neutral atoms

The solar wind blows an immense magnetic bubble, the heliosphere, in the local interstellar medium (mostly neutral gas) flowing by the Sun. Recent measurements by Voyager 2 across the termination shock, where the solar wind is slowed to subsonic speeds before entering the heliosheath, found that the shocked solar wind plasma contains only approximately 20 per cent of the energy released by the termination shock, whereas energetic particles above approximately 28 keV contain only approximately 10 per cent; approximately 70 per cent of the energy is unaccounted for, leading to speculation that the unmeasured pickup ions or energetic particles below 28 keV contain the missing energy. Here we report the detection and mapping of heliosheath energetic ( approximately 4-20 keV) neutral atoms produced by charge exchange of suprathermal ions with interstellar neutral atoms. The energetic neutral atoms come from a source approximately 60 degrees wide in longitude straddling the direction of the local interstellar medium. Their energy spectra resemble those of solar wind pickup ions, but with a knee at approximately 11 keV instead of approximately 4 keV, indicating that their parent ions are pickup ions energized by the termination shock. These termination-shock-energized pickup ions contain the missing approximately 70 per cent of the energy dissipated in the termination shock, and they dominate the pressure in the heliosheath.     

Biodiversity and biogeography of phages in modern stromatolites and thrombolites

Viruses, and more particularly phages (viruses that infect bacteria), represent one of the most abundant living entities in aquatic and terrestrial environments. The biogeography of phages has only recently been investigated and so far reveals a cosmopolitan distribution of phage genetic material (or genotypes). Here we address this cosmopolitan distribution through the analysis of phage communities in modern microbialites, the living representatives of one of the most ancient life forms on Earth. On the basis of a comparative metagenomic analysis of viral communities associated with marine (Highborne Cay, Bahamas) and freshwater (Pozas Azules II and Rio Mesquites, Mexico) microbialites, we show that some phage genotypes are geographically restricted. The high percentage of unknown sequences recovered from the three metagenomes (>97%), the low percentage similarities with sequences from other environmental viral (n = 42) and microbial (n = 36) metagenomes, and the absence of viral genotypes shared among microbialites indicate that viruses are genetically unique in these environments. Identifiable sequences in the Highborne Cay metagenome were dominated by single-stranded DNA microphages that were not detected in any other samples examined, including sea water, fresh water, sediment, terrestrial, extreme, metazoan-associated and marine microbial mats. Finally, a marine signature was present in the phage community of the Pozas Azules II microbialites, even though this environment has not been in contact with the ocean for tens of millions of years. Taken together, these results prove that viruses in modern microbialites display biogeographical variability and suggest that they may be derived from an ancient community.     

Dll4 signalling through Notch1 regulates formation of tip cells during angiogenesis

In sprouting angiogenesis, specialized endothelial tip cells lead the outgrowth of blood-vessel sprouts towards gradients of vascular endothelial growth factor (VEGF)-A. VEGF-A is also essential for the induction of endothelial tip cells, but it is not known how single tip cells are selected to lead each vessel sprout, and how tip-cell numbers are determined. Here we present evidence that delta-like 4 (Dll4)-Notch1 signalling regulates the formation of appropriate numbers of tip cells to control vessel sprouting and branching in the mouse retina. We show that inhibition of Notch signalling using gamma-secretase inhibitors, genetic inactivation of one allele of the endothelial Notch ligand Dll4, or endothelial-specific genetic deletion of Notch1, all promote increased numbers of tip cells. Conversely, activation of Notch by a soluble jagged1 peptide leads to fewer tip cells and vessel branches. Dll4 and reporters of Notch signalling are distributed in a mosaic pattern among endothelial cells of actively sprouting retinal vessels. At this location, Notch1-deleted endothelial cells preferentially assume tip-cell characteristics. Together, our results suggest that Dll4-Notch1 signalling between the endothelial cells within the angiogenic sprout serves to restrict tip-cell formation in response to VEGF, thereby establishing the adequate ratio between tip and stalk cells required for correct sprouting and branching patterns. This model offers an explanation for the dose-dependency and haploinsufficiency of the Dll4 gene, and indicates that modulators of Dll4 or Notch signalling, such as gamma-secretase inhibitors developed for Alzheimer's disease, might find usage as pharmacological regulators of angiogenesis.     

PART 2: Critical Systemic Praxis to Address Fixed and Fluid Identity and Politics<Superscript>1</Superscript> at the Local,National and International Level

This paper argues for a model of systemic governance that can take account of diverse identities and political positions (Deleuze and Guattari in Bogue, 1989). Participatory Action Research can assist in working with diverse viewpoints when managing and making policy decisions across many organizations locally, nationally and internationally. Understanding the point of view of ‘the other’ and the recursive nature of identity and politics is the first step towards sustainable governance. Enabling multiple viewpoints to be heard is both an idealistic and sustainable end and a means to manage risk. Accountability needs to ‘sweep in’ and ‘unfold’ (Churchman, 1979a,b, 1982) social, cultural, economic and environmental factors (adapting Elkington, 1997, drawing on Banathy, 1996, 2000; Laszlo, 1991; Laszlo, and Laszlo, 2004). Participatory governance needs to address questions about fixed and fluid politics and identity. These questions address cultural norms, bonds and boundaries (Elias and Lichterman, 2003) to guide reflection on cases that strive to achieve accountability. Experiential learning through participatory action research with the most marginalised in society and listening to significant others (whose systemic praxis) is the basis for the theory on systemic governance.¹Paper is drawn from forthcoming book entitled: “Systemic Governance: Working and re-working the conceptual and geographical boundaries of governance and international relations” (2005) and parts of the paper were presented at the 49th Annual Conference of the International Systems Sciences Asilomar 2004. A more detailed version of the case study on the hijab has been submitted for consideration as a publication on human rights and governance to Systems Research and Behavioural Science October 2004. References to Churchman’s work have also been made in Critical Systemic Praxis for Social and Environmental Justice (2003)Kluwer.