Environmental Dependency of Inbreeding Depression: Implications for Conservation Biology

Inbreeding depression is environmentally dependent, such that a population may suffer from inbreeding depression in one environment but not another. We examined the phenotypic responses of 35 inbred ( F = 0.672) lineages of the red flour beetle Tribolium castaneum in two different climatic environments. We found a significant environmental effect on males but not females. More important, we found that the rank fitness order of lineages differs between environments; lineages of high fitness in one environment may have low fitness in another environment. This change in rank is evident in a significant genotype-by-environment interaction for inbreeding depression for both females and males. These results suggest that even if we know the average environmental effect of inbreeding depression in a population, for any particular lineage measurements of inbreeding depression in one environment may not predict the level of inbreeding depression in another environment. Conservation biologists need to be aware of the environmental dependency of inbreeding depression when planning wildlife refuges or captive propagation programs for small populations. Ideally, captive propagation programs should maintain separate lineages for release efforts. Refuge design programs should consider maintaining a range of habitat types.     

Challenges to mobilising resources for disaster recovery and reconstruction: perspectives of the Haitian diaspora

Diasporas and diaspora non‐governmental organisations (NGOs) are increasingly important as resource lifelines to their home countries, yet the resources that they mobilise, the types of challenges that they face, and their coping mechanisms are not well explored or understood in the context of disaster recovery. To fill this knowledge gap, this study employed an inductive qualitative methodological approach, using interviews to comprehend the role played by Haitian diaspora NGOs after the catastrophic earthquake in 2010. It found that resources take four common forms: event fundraisers; financial and material donations from supporters; remittances; and volunteer labour. Challenges include an overreliance on diaspora donors, competition among NGOs, and what is perceived as inequitable funding practices towards diaspora NGOs. The findings provide insights centred on better coordination among diaspora NGOs, as well as between diaspora NGOs and other local and international NGOs and local governments and international institutions, to ensure more efficient delivery of services to survivors.     

Evolution of the fast start response in the cavefish Astyanax mexicanus

The extreme sensory environment of subterranean caves presents an adaptive challenge for troglobitic organisms. Although caves provide distinct selective pressures (e.g., darkness, food scarcity), advantages often come with living in isolated places. The cave-adapted (hypogean) form of the teleost Astyanax mexicanus lacks predators in its natural environment, unlike its ancestral surface (epigean) form that inhabits the nearby rivers. This species provides a unique opportunity for comparative studies because A. mexicanus has invaded the cave environment multiple times, providing us with independent comparative adaptive experiments. Here, we examine kinematic parameters that characterize the escape responses of various forms of A. mexicanus. We demonstrate that populations differ in details of fast start performance, but that surface fish do not perform better than cavefish in escape responses. Our results are more consistent with genetic drift or divergent selection among caves than with relaxation of selection in determining the evolution of escape behavior in this system.     

Characterization of controlled-release KMnO4 (CRP) barrier system for groundwater remediation: a pilot-scale flow-tank study

Release and spreading of permanganate (MnO(4)(-)) in the well-based controlled-release potassium permanganate (KMnO(4)) barrier system (CRP system) was investigated by conducting column release tests, model simulations, soil oxidant demand (SOD) analyses, and pilot-scale flow-tank experiments. A large flow tank (L x W x D=8m x 4m x 3m) was constructed. Pilot-scale CRP pellets (OD x L=0.05 m x1.5m; n=110) were manufactured by mixing approximately 198 kg of KMnO(4) powders with paraffin wax and silica sands in cylindrical moulds. The CRP system (L x W x D=3m x 4m x 1.5m) comprising 110 delivery wells in three discrete barriers was constructed in the flow tank. Natural sands (organic carbon content=0.18%; SOD=3.7-11 g MnO(4)(-)kg(-1)) were used as porous media. Column release tests and model simulations indicated that the CRP system could continuously release MnO(4)(-) over several years, with slowly decreasing release rates of 2.5 kg d(-1) (day one), 109 g d(-1) (day 100), 58 g d(-1) (year one), 22 g d(-1) (year five), and 12 g d(-1) (year 10). Mean MnO(4)(-) concentrations within the CRP system ranged from 0.5 to 6 mg l(-1) during the 42 days of testing period. The continuously releasing MnO(4)(-) was gradually removed by SOD limiting the length of MnO(4)(-) zone in the porous media. These data suggested that the CRP system could create persistent and confined oxidation zone in the subsurface. Through development of advanced tools for describing agent transport and facilitating lateral agent spreading, the CRP system could provide new approach for long-term in situ treatment of contaminant plumes in groundwater.     

Tests appropriate for the prenatal diagnosis of ataxia telangiectasia

A fetus ‘at-risk’ for ataxia telangiectasia (A-T) was monitored prenatally by several approaches which, in concert, might yield information of diagnostic value: measurement of amniotic fluid AFP levels; the clastogenic potential of ‘at-risk’ amniotic fluid; and cytogenic evaluation of fetal amniocytes. All three parameters proved negative and normality, based primarily on the chromosomal study of fetal cells, was therefore presumed. This conclusion was confirmed shortly after birth by normal serum AFP levels and the lack of increased spontaneous or clastogen-induced chromosome breakage in the infant's cells. Based on previous observations from four normal and one affected fetus, the coordination of these techniques provides adequate methodology for the antenatal assessment of the phenotypes associated with A-T.     

Chemical evolution: The first stages

The available data on the syntheses of critically important precursor molecules for chemical evolution are reviewed and problems of rates of production versus rates of destruction in the primitive ocean are discussed. It is concluded that many global chemical syntheses would have been improbable in the Earth's oceans and that more attention should be paid to specific environments which would have favored such syntheses. The recent discovery of an accelerating effect of formaldehyde on the oligomerization of HCN as well as the eutectic-concentration mechanism are discussed in relation to a new scenario for chemical evolution on the primitive Earth.     

Prenatal detection of trisomy 9 mosaicism

Chromosomal mosaicism in amniotic fluid cells poses a serious dilemma in prenatal diagnosis since the observation may represent: (1) pseudomosaicism—an inconsequential tissue culture artefact; or (2) true mosaicism—occurring in approximately 0.0 per cent of amniocenteses with a significant impact on pregnancy outcome. Mosaicism for trisomy 9 was observed in an amniotic fluid specimen obtained for advanced maternal age with two cell lines [46,XX (46 per cent)/47,XX, + 9 (54 per cent)] present in each of four culture flasks. Since more than 75 per cent of newborns with trisomy 9 mosaicism have complex cardiac malformations, a fetal echocardiogram was obtained at 20 weeks' gestation and interpreted as normal. A fetal blood sample (22 weeks' gestation) disclosed only a single trisomy 9 cell among the 100 metaphases analysed. However, a second fetal echocardiogram performed at the time of blood sampling suggested a non-specific cardiac anomaly. Fetal autopsy following elective pregnancy termination revealed several malformations including severe micrognathia, persistence of the left superior vena cava, and skeletal anomalies. Cytogenetic studies of cell cultures derived from several fetal tissues demonstrated trisomy 9 ranging from 12 to 24 per cent.