A Cladistic Analysis of \u3cem\u3endh\u3c/em\u3eF Sequences from Representative Species of \u3cem\u3eSaintpaulia\u3c/em\u3e and \u3cem\u3eStreptocarpus\u3c/em\u3e Subgenera and \u3cem\u3eStreptocarpella\u3c/em\u3e (Gesneriaceae)

Two African genera of the Gesneriaceae, Saintpaulia and Streptocarpus, are similar in many respects. Both genera have blue to purple flowers, pollen of similar shape and exine sculpting, embryos with one-celled uninucleate chalazal haustoria, shared vegetative structures among some species, and are among the few genera in the Gesneriaceae which include species with chromosome count of n=15. Similarity of these features has indicated that the two genera are likely to be closely related. This study examines the sequences of the chloroplast gene ndhF among several representative Saintpaulia and representatives of Streptocarpus subgenera Streptocarpella and Streptocarpus. The results of this analysis are congruent with those of previous analysis based on the nuclear ribosomal region, ITS. Saintpaulia was found to be nested within Streptocarpus and Streptocarpella. The results raise the possibility of the taxonomic revision of these genera, and this is discussed. Comparisons between the data sets are made regarding utility of the two regions, sample size and outgroup

Cross-cultural invariances in the architecture of shame

This set of experiments shows that in 15 traditional small-scale societies there is an extraordinarily close correspondence between (i) the intensity of shame felt if one exhibited specific acts or traits and (ii) the magnitude of devaluation expressed in response to those acts or traits by local audiences, and even foreign audiences. Three important and widely acknowledged sources of cultural variation between communities—}geographic proximity, linguistic similarity, and religious similarity{—}all failed to account for the strength of between-community correlations in the shame{–}devaluation link. This supplies a parallel line of evidence that shame is a universal system, part of our species{’} cooperative biology, rather than a product of cultural evolution.Human foragers are obligately group-living, and their high dependence on mutual aid is believed to have characterized our species{’} social evolution. It was therefore a central adaptive problem for our ancestors to avoid damaging the willingness of other group members to render them assistance. Cognitively, this requires a predictive map of the degree to which others would devalue the individual based on each of various possible acts. With such a map, an individual can avoid socially costly behaviors by anticipating how much audience devaluation a potential action (e.g., stealing) would cause and weigh this against the action{’}s direct payoff (e.g., acquiring). The shame system manifests all of the functional properties required to solve this adaptive problem, with the aversive intensity of shame encoding the social cost. Previous data from three Western(ized) societies indicated that the shame evoked when the individual anticipates committing various acts closely tracks the magnitude of devaluation expressed by audiences in response to those acts. Here we report data supporting the broader claim that shame is a basic part of human biology. We conducted an experiment among 899 participants in 15 small-scale communities scattered around the world. Despite widely varying languages, cultures, and subsistence modes, shame in each community closely tracked the devaluation of local audiences (mean r = +0.84). The fact that the same pattern is encountered in such mutually remote communities suggests that shame{’s match to audience devaluation is a design feature crafted by selection and not a product of cultural contact or convergent cultural evolution

The role of immigrants in the assembly of the South American rainforest tree flora

The Amazon lowland rainforest flora is conventionally viewed as comprising lineages that evolved in biogeographic isolation after the split of west Gondwana (ca. 100 Myr ago). Recent molecular phylogenies, however, identify immigrant lineages that arrived in South America during its period of oceanic isolation (ca. 100–3 Myr ago). Long-distance sweepstakes dispersal across oceans played an important and possibly predominant role. Stepping-stone migration from Africa and North America through hypothesized Late Cretaceous and Tertiary island chains may have facilitated immigration. An analysis of inventory plot data suggests that immigrant lineages comprise ca. 20% of both the species and individuals of an Amazon tree community in Ecuador. This is more than an order of magnitude higher than previous estimates. We also present data on the community-level similarity between South American and palaeotropical rainforests, and suggest that most taxonomic similarity derives from trans-oceanic dispersal, rather than a shared Gondwanan history.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/83303/1/Pennington2004.pd

Taxonomic surrogacy in biodiversity assessments, and the meaning of Linnaean ranks

Copyright © 2006 The Natural History MuseumThe majority of biodiversity assessments use species as the base unit. Recently, a series of studies have suggested replacing numbers of species with higher ranked taxa (genera, families, etc.); a method known as taxonomic surrogacy that has an important potential to save time and resources in assesments of biological diversity. We examine the relationships between taxa and ranks, and suggest that species/higher taxon exchanges are founded on misconceptions about the properties of Linnaean classification. Rank allocations in current classifications constitute a heterogeneous mixture of various historical and contemporary views. Even if all taxa were monophyletic, those referred to the same rank would simply denote separate clades without further equivalence. We conclude that they are no more comparable than any other, non-nested taxa, such as, for example, the genus Rattus and the phylum Arthropoda, and that taxonomic surrogacy lacks justification. These problems are also illustrated with data of polychaetous annelid worms from a broad-scale study of benthic biodiversity and species distributions in the Irish Sea. A recent consensus phylogeny for polychaetes is used to provide three different family-level classifications of polychaetes. We use families as a surrogate for species, and present Shannon–Wiener diversity indices for the different sites and the three different classifications, showing how the diversity measures rely on subjective rank allocations.Y. Bertrand, F. Pleijel and G. W. Rous

Soil seed bank of the invasive Robinia pseudoacacia in planted Pinus nigra stands

Pinus nigra and Robinia pseudoacacia are exotic trees used for afforestation in Hungary. Pinus nigra was non-invasive, however R. pseudoacacia escaped from cultivation and invaded several vegetation types including pine plantations. It has recently been planned to cut P. nigra plantations and replace them by native tree stands, especially in nature reserves. The scattered presence of R. pseudoacacia specimens in pine stands might place constraints on planned tree replacement because of their vegetative resprouting and recolonization from an established seed bank. The aim of this study was to investigate the soil seed bank under the canopy of solitary R. pseudoacacia specimens found in P. nigra plantations. Altogether 250 soil samples were collected from the 0–6 and 6–12 cm soil layers under solitary Robinia trees of varying ages (with basal areas between 62.4 and 1089.3 cm2). Seeds were separated by sieving then scarified and germinated. Seed bank density ranged between 640 and 2285 seedsm–2 with an average distribution of 82.7% and 17.3% in the upper and lower soil layer, respectively. Total density of the seed bank and also the seed bank ratio of the lower soil layer increased with tree age. The accumulated seed bank of R. pseudoacacia should be considered in the careful planning of tree replacement operations in Pinus nigra stands

Contribution of NFP LysM Domains to the Recognition of Nod Factors during the Medicago truncatula/Sinorhizobium meliloti Symbiosis

The root nodule nitrogen fixing symbiosis between legume plants and soil bacteria called rhizobia is of great agronomical and ecological interest since it provides the plant with fixed atmospheric nitrogen. The establishment of this symbiosis is mediated by the recognition by the host plant of lipo-chitooligosaccharides called Nod Factors (NFs), produced by the rhizobia. This recognition is highly specific, as precise NF structures are required depending on the host plant. Here, we study the importance of different LysM domains of a LysM-Receptor Like Kinase (LysM-RLK) from Medicago truncatula called Nod factor perception (NFP) in the recognition of different substitutions of NFs produced by its symbiont Sinorhizobium meliloti. These substitutions are a sulphate group at the reducing end, which is essential for host specificity, and a specific acyl chain at the non-reducing end, that is critical for the infection process. The NFP extracellular domain (ECD) contains 3 LysM domains that are predicted to bind NFs. By swapping the whole ECD or individual LysM domains of NFP for those of its orthologous gene from pea, SYM10 (a legume plant that interacts with another strain of rhizobium producing NFs with different substitutions), we showed that NFP is not directly responsible for specific recognition of the sulphate substitution of S. meliloti NFs, but probably interacts with the acyl substitution. Moreover, we have demonstrated the importance of the NFP LysM2 domain for rhizobial infection and we have pinpointed the importance of a single leucine residue of LysM2 in that step of the symbiosis. Together, our data put into new perspective the recognition of NFs in the different steps of symbiosis in M. truncatula, emphasising the probable existence of a missing component for early NF recognition and reinforcing the important role of NFP for NF recognition during rhizobial infection

Spreading order: religion, cooperative niche construction, and risky coordination problems

Adaptationists explain the evolution of religion from the cooperative effects of religious commitments, but which cooperation problem does religion evolve to solve? I focus on a class of symmetrical coordination problems for which there are two pure Nash equilibriums: (1) ALL COOPERATE, which is efficient but relies on full cooperation; (2) ALL DEFECT, which is inefficient but pays regardless of what others choose. Formal and experimental studies reveal that for such risky coordination problems, only the defection equilibrium is evolutionarily stable. The following makes sense of otherwise puzzling properties of religious cognition and cultures as features of cooperative designs that evolve to stabilise such risky exchange. The model is interesting because it explains lingering puzzles in the data on religion, and better integrates evolutionary theories of religion with recent, well-motivated models of cooperative niche construction

Cardiac sodium channelopathies

Cardiac sodium channel are protein complexes that are expressed in the sarcolemma of cardiomyocytes to carry a large inward depolarizing current (INa) during phase 0 of the cardiac action potential. The importance of INa for normal cardiac electrical activity is reflected by the high incidence of arrhythmias in cardiac sodium channelopathies, i.e., arrhythmogenic diseases in patients with mutations in SCN5A, the gene responsible for the pore-forming ion-conducting α-subunit, or in genes that encode the ancillary β-subunits or regulatory proteins of the cardiac sodium channel. While clinical and genetic studies have laid the foundation for our understanding of cardiac sodium channelopathies by establishing links between arrhythmogenic diseases and mutations in genes that encode various subunits of the cardiac sodium channel, biophysical studies (particularly in heterologous expression systems and transgenic mouse models) have provided insights into the mechanisms by which INa dysfunction causes disease in such channelopathies. It is now recognized that mutations that increase INa delay cardiac repolarization, prolong action potential duration, and cause long QT syndrome, while mutations that reduce INa decrease cardiac excitability, reduce electrical conduction velocity, and induce Brugada syndrome, progressive cardiac conduction disease, sick sinus syndrome, or combinations thereof. Recently, mutation-induced INa dysfunction was also linked to dilated cardiomyopathy, atrial fibrillation, and sudden infant death syndrome. This review describes the structure and function of the cardiac sodium channel and its various subunits, summarizes major cardiac sodium channelopathies and the current knowledge concerning their genetic background and underlying molecular mechanisms, and discusses recent advances in the discovery of mutation-specific therapies in the management of these channelopathies