Shape plasticity in response to water velocity in the freshwater blenny Salaria fluviatilis

A non‐random association between an environmental factor and a given trait could be explained by directional selection (genetic determinism) and by phenotypic plasticity (environmental determinism). A previous study showed a significant relationship between morphology and water velocity in Salaria fluviatilis that conformed to functional expectations. The objective of this study was to test whether this relationship could be explained by phenotypic plasticity. Salaria fluviatilis from a Corsican stream were placed in four experimental channels with different water velocities (0, 10, 20 and 30 cm s^?1) to test whether there was a morphological response associated with this environmental factor. After 28 days, fish shape changed in response to water velocity without any significant growth. Fish in higher water velocities exhibited a more slender body shape and longer anal and caudal fins. These results indicate a high degree of morphological plasticity in riverine populations of S. fluviatilis and suggest that the previous relationship between morphology and water velocity observed in the field may largely be due to an environmental determinism.     

High levels of genetic structure and striking phenotypic variability in a sexually dimorphic suckermouth catfish from the African Highveld

Uncovering biological diversity to more accurately understand diversity patterns, and ultimately the processes driving diversification, is important not only from an evolutionary perspective but also a conservation perspective. This is particularly pertinent in Africa's rivers in which overall diversity, as well as how it arose, is poorly understood in comparison with lacustrine environments. Here we investigate population divergence in the sexually dimorphic suckermouth catfish species Chiloglanis anoterus (Crass, 1960) from the African Highveld, in which we observe striking variability in exaggerated male caudal fins across its range. As this trait is likely to be indirect evidence for sexual selection by female choice, a mechanism that has been shown to increase species diversity in different taxa, we used an integrated approach to test if current diversity in this species is underestimated. Results based on phylogenetic inference, population genetics and geometric morphometrics indicate that the recognized species C. anoterus represents five distinct lineages that may be considered confirmed candidate species. We suggest that diversification in these highland catfish has been facilitated through geographical isolation in upper river catchments, and that sexual selection through female choice has probably driven variation in male caudal fin morphology. In contrast to the relatively large range size of the currently recognized species (C. anoterus), our findings highlight highly restricted ranges of the lineages identified here, indicating that these highland habitats may harbour higher levels of endemic diversity than previously thought.     

Long‐term survival and diversification of an endemic Melitaea species in mountains of Iran and adjacent areas

Disjunct distribution patterns regularly resulted in the separation of different genetic lineages in glacial refugia. Recent patterns of survival and expansion have been often revealed by climatic niche modelling. We used the combination of genetic markers, geometric morphometry and climatic niche modelling to clear up the taxonomy and reconstruct the potential range of an endemic Iranian, taxonomically disputed Melitaea species in climatically different epochs. Our results show that this species (Melitaea abbas Gross and Ebert 1975, comb. n. = M. zagrosi Tóth and Varga syn. nova) is clearly separated from all taxa of the Melitaea phoebe species group and only occurs in Iran and Azerbaijan but were also predicted for some adjacent regions. Molecular markers and distribution modelling show consistently that this species should have had a long‐term survival in this area, and its range could have been slightly larger during the last glacial maximum than currently. Based on the studied molecular markers, three main groups in M. abbas can be recognized: those of steppic area of Azerbaijan, western Iran and northeastern Iran. Each group is characterized by own mitochondrial haplotypes, but also a high level of genetic diversity appears in the central part of the distribution area (Zagros Mts.).     

A null model for species richness gradients: bounded range overlap of butterflies and other rainforest endemics in Madagascar

Species richness has classically been thought to increase from the poles towards the Equator, and from high elevations down to sea-level. However, the largest radiation of butterflies in Madagascar, the subtribe Mycalesina (c. 67 spp.) does not exhibit such a monotonic pattern, either for empirical records or for interpolated species ranges. Instead, summation of mycalesine ranges generates a domed curve of species richness values approximately symmetric around mid latitudes within the island, a pattern most smoothly exhibited by the wider ranging and better known species, and a less symmetric curve peaking near mid elevations. Hotspots for the summation of 1183 species ranges and seven out of the ten groups of insects and vertebrates analysed (butterflies, cicindelid and enariine melonthid beeties, ctenuchiine moths, chameleons, frogs, birds, lemurs, tenrecs, and rodents) also occur at both mid latitudes and elevations. The most strongly parabolic pattern is shown by animals (637 spp.) whose ranges are confined to the highly linear rainforest biome. This rainforest species richness curve is resilient in shape even after controlling for particular effects of area and irregular sample effort. In sharp contrast, at least eight different environmental parameters for the rainforest biome tend to increase monotonically towards the northern, more tropical, boundary, a trend evident only in species richness gradients of more narrow-ranging species. The one-dimensional latitudinal species richness curves and hotspots observed in fact best reflect overall the geometric predictions of a null model for ranked range size partitions of the regional species pool. This analytical model is based on the uniform probability distribution, and assumes that species ranges are constrained by the position of biome or island boundaries. The same logarithmic equations applied iteratively to longitude also accurately predict hotspots for more realistic species ranges containing gaps, as shown for two-dimensional species richness patterns for the Madagascan rainforest dataset. Bio-geographic and conservation implications of the bounded range overlap concept are discussed.     

一种简便、快速的大肠杆菌质粒转化方法

将受体菌与质粒DNA混匀直接在Ca2+离子选择平板上进行转化和筛选,其转化过程仅需2 min左右,并能得到105以上的转化效率, 可满足一般克隆工作的需要。 Abstract：After mixing the recipient cells and plasmids DNA, directly spread the mixture on selective media containing Ca2+. The whole process of transformation just needs 2 min or so, and could acquire the transformation efficiency of more than 105, which is enough to common gene cloning.     

Statistical considerations for in vitro research: II — Data to presentation

Summary The paper is the second of two papers about statistical considerations that researchers should make while doing in vitro plant biology research. The first paper focused on aspects from developing a plan to do research through the collection of data. This paper continues with information about editing data, handling outliers, analyzing quantitative and qualitative data, comparing treatment means, preparing graphs and tables, and presenting results.     

Some Exploratory Methods for Studying Curvature in Robust Regression

The paper suggests an exploratory method for studying curvature, within the context of robust regression, using an analog of the approached developed by Doksum and Samarov (1995). The strategy begins by approximating the regression surface using a proposed generalization of the so‐called running interval smoother. The generalization consists of estimating the span via arobust measure of scale associated with the residuals. This approximation can then be used to measure linearity using a robust analog of a measure considered by Doksum and Samarov. The results are illustrated with data from a study on predicting reading ability.     

Bayesian Inference for the Ratio of the Means of Two Normal Populations with Unequal Variances

The problem of making inferences about the ratio of two normal means has been addressed, both from the frequentist and Bayesian perspectives, by several authors. Most of this work is concerned with the homoscedastic case. In contrast, the situation where the variances are not equal has received little attention. Cox (1985) deals, within the frequentist framework, with a model where the variances are related to the means. His results are mainly based on Fieller's theorem whose drawbacks are well known. In this paper we present a Bayesian analysis of this model and discuss some related problems. An agronomical example is used throughout to illustrate the methods.     

Genome‐scale data reveal that endemic Poecilia populations from small sulphidic springs display no evidence of inbreeding

Populations with limited ranges can be highly vulnerable to changes in their environment and are, thus, of high conservation concern. Populations that experience human‐induced range reductions are often highly inbred and lack genetic diversity, but it is unknown whether this is also the case for populations with naturally small ranges. The fishes Poecilia sulphuraria (listed as critically endangered) and Poecilia thermalis, which are endemic to small hydrogen sulphide‐rich springs in southern Mexico, are examples of such populations with inherently small habitats. We used geometric morphometrics and population genetics to quantify phenotypic and genetic variation within and among two populations of P. sulphuraria and one population of P. thermalis. Principal component analyses revealed phenotypic and genetic differences among the populations. Evidence for inbreeding was low compared to populations that have undergone habitat reduction. The genetic data were also used to infer the demographic history of these populations to obtain estimates for effective population sizes and migration rates. Effective population sizes were large given the small habitats of these populations. Our results imply that these three endemic extremophile populations should each be considered separately for conservation purposes. Additionally, this study suggests that populations in naturally small habitats may have lower rates of inbreeding and higher genetic diversity than expected, and therefore may be better equipped to handle environmental perturbations than anticipated. We caution, however, that the inferred lack of inbreeding and the large effective population sizes could potentially be a result of colonization by genetically diverse ancestors.     

Isolation and spectral characterization of thermally generated multi-Z-isomers of lycopene and the theoretically preferred pathway to di-Z-isomers

Lycopene has a large number of geometric isomers caused by E/Z isomerization at arbitrary sites within the 11 conjugated double bonds, offering varying characteristics related to features such as antioxidant capacity and bioavailability. However, the geometric structures of only a few lycopene Z-isomers have been thoroughly identified from natural sources. In this study, seven multi-Z-isomers of lycopene, (9Z,13′Z)-, (5Z,13Z,9′Z)-, (9Z,9′Z)-, (5Z,13′Z)-, (5Z,9′Z)-, (5Z,9Z,5′Z)-, and (5Z,9Z)-lycopene, were obtained from tomato samples by thermal isomerization, and then isolated by elaborate chromatography, and fully assigned using proton nuclear magnetic resonance. Moreover, the theoretically preferred pathway from (all-E)-lycopene to di-Z-isomers was examined with a computational approach using a Gaussian program. Fine-tuning of the HPLC separation conditions led to the discovery of novel multi-Z-isomers, and whose formation was supported by advanced theoretical calculations.