Do Chinese cavefish show intraspecific variability in morphological traits?

Cavefishes represent one of the most bizarre and intriguing life forms inhabiting groundwater environments. One‐third of the known cavefishes worldwide is endemic to China, and almost half of those belongs to a single genus, Sinocyclocheilus (Cypriniformes: Cyprinidae). Analyzing the morphometrics of three Sinocyclocheilus species, we aimed to assess whether variability among conspecific populations exists. We predict that populations inhabiting different subterranean habitats (shallow vs. deep) show divergences in specific morphological traits to better cope with the local ecological conditions. Our results showed that the populations showing bigger eyes and reduced humpback were those occurring close to the cave entrance (habitats with light and high food availability), while specimens with smaller eyes and increased humpback were collected from deeper groundwater areas (habitats laying in darkness with food scarcity). This explorative study paves the way for further researches aiming to collect novel data on Chinese cavefishes and highlights the usefulness of these species in evolutionary studies.     

Do “antisense proteins” exist?

A DNA double helix consists of two complementary strands antiparallel with each other. One of them is the sense chain, while the other is an antisense chain which does not directly involve the protein-encoding process. The reason that an antisense chain cannot encode for a protein is generally attributed to the lack of certain preconditions such as a promotor and some necessary sequence segments. Suppose it were provided with all these preconditions, could an antisense chain encode for an antisense protein? To answer this question, an analysis has been performed based on the existing database. Nine proteins have been found that have a 100% sequence match with the hypothetical antisense proteins derived from the knownEscherichia coli antisense chains.On sabbatical leave from Department of Physics, Tianjin University, Tianjin, China.     

Direct radioimmunoassay of estradiol-17β in defatted bovine milk

A radioimmunoassay was developed for rapid determination of estradiol-17β concentrations in unextracted defatted bovine milk. The assay was dependent on the use of a highly specific anti-estradiol-17β antiserum. Application of a formula to correct for the interference associated with individual milk samples and use of appropriate assay blanks facilitated interpolation on a buffer standard curve. The assay offered a high degree of sensitivity (0.6pg/ml milk) and a precision (within-assay coefficient of variation: 0.196; between-assay CV:0.191) comparable with contemporary extraction methods.     

Do different speed types of action potentials exist in higher plants?

The problem of paradoxically different values of speeds of the propagation of action potentials in conduction pathways of higher plants is considered. Possible causes of this phenomenon are discussed.     

Do generalized scaling laws exist for species abundance distribution in mountains?

Knowing the global pattern of species diversity is a central goal of the science of ecology, and scaling laws can be useful for analysis of cross-scale biodiversity patterns. An elevational gradient in a warm temperate zone of the Donglingshan mountains (China) is used to test the scaling laws of species abundance distribution using multifractal analysis. We show that the power law scaling relationship holds for not just the classical SAR (species–area relationship for richness), but also for Shannon and Simpson diversity. In fact, we find power-laws in the generalized species abundance distribution at all stratal levels of the forest (trees, shrubs and herbs). The fact that these laws exist across a heterogeneous landscape representing a strong bioclimatic gradient suggests that biodiversity scaling laws may be more robust than previously thought.     

Do early branching lineages signify ancestral traits?

A reverence for ancestors that has pre-occupied humans since time immemorial persists to the present. Reconstructing ancestry is the focus of many biological studies but failure to distinguish between present-day descendants and long-dead ancestors has led to incorrect interpretation of phylogenetic trees. This has resulted in erroneous reconstruction of traits such as morphology and ancestral areas. Misinterpretation becomes evident when authors use the terms 'basal' or 'early diverging' to refer to extant taxa. Here, we discuss the correct interpretation of trees and methods for reconstructing the ancestral features of organisms using recently developed statistical models. These models can be inaccurate unless they use information that is independent of phylogenies, such as genetics, molecular and developmental biology, functional morphology, geological and climatic processes, and the fossil record.     

Do laying hens eat and forage in excreta from other hens?

Worldwide, farm animals are kept on litter or foraging substrate that becomes increasingly soiled throughout the production cycle. For animals like laying hens, this means that it is likely they would scratch, forage and consume portions of excreta found in the litter or foraging substrate. However, no study has investigated the relative preference of laying hens for foraging and consumption of feed mixed with different percentages of excreta. A total of 48 White Leghorn laying hens of two strains, a commercial strain (Lohmann LSL-Lite (LSL), n=24) and UCD-003 strain (susceptible to liver damage, n=24), were individually housed and given access to feed mixed with increasing percentages of hen excreta (0%, 33%, 66% and 100% excreta diets) and corn as a luxury food reward (four corn kernels per diet daily). The amount of substrate and number of corn kernels consumed from each diet was recorded for a period of 3 weeks. Both LSL and UCD-003 hens preferred to consume and forage in diets with 0% excreta, followed by 33% and finally diets containing 66% and 100% excreta. Despite the presence of excreta-free diets, birds consumed on average 61.3 g per day of the diets containing excreta. Neither physical health, measured by plasma enzyme activity levels, nor cognitive differences, assessed by recalling a visual discrimination task, was associated with relative feeding or foraging preference. In conclusion, this study demonstrated a clear preference for feeding and foraging on substrate without excreta in laying hens. However, considering the amount of excreta diets consumed, further studies are needed to understand the causes and consequences of excreta consumption on physiological and psychological functioning, and how this information can be used to allow adjustments in the management of foraging substrates in farmed birds.     

Do molecular markers reflect patterns of differentiation in adaptive traits of conifers?

We have examined patterns of variation of several kinds of molecular markers (isozymes, RFLPs of ribosomal DNA and anonymous low-copy number DNA, RAPDs and microsatellites) and an adaptive trait [date of bud set in Scots pine (Pinus sylvestris L.)]. The study included Finnish Scots pine populations (from latitude 60°N to 70°N) which experience a steep climatic gradient. Common garden experiments show that these populations are adapted to the location of their origin and genetically differentiated in adaptive quantitative traits, e.g. the date of bud set in first-year seedlings. In the northernmost population, bud set took place about 21 days earlier than in the southernmost population. Of the total variation in bud set, 36.4% was found among the populations. All molecular markers showed high levels of within-population variation, while differentiation among populations was low. Among all the studied markers, microsatellites were the most variable (H_e=0.77). Differences between populations were small, G_ST was less than 0.02. Our study suggests that molecular markers may be poor predictors of the population differentiation of quantitative traits in Scots pine, as exemplified here by bud-set date.     

Do human ‘life history strategies’ exist?

Interest in incorporating life history research from evolutionary biology into the human sciences has grown rapidly in recent years. Two core features of this research have the potential to prove valuable in strengthening theoretical frameworks in the health and social sciences: the idea that there is a fundamental trade-off between reproduction and health; and that environmental influences are important in determining how life histories develop. However, the literature on human life histories has increasingly travelled away from its origins in biology, and become conceptually diverse. For example, there are differences of opinion between evolutionary researchers about the extent to which behavioural traits associate with life history traits to form ‘life history strategies’. Here, I review the different approaches to human life histories from evolutionary anthropologists, developmental psychologists and personality psychologists, in order to assess the evidence for human ‘life history strategies’. While there is precedent in biology for the argument that some behavioural traits, notably risk-taking behaviour, may be linked in predictable ways with life history traits, there is little theoretical or empirical justification for including a very wide range of behavioural traits in a ‘life history strategy’. Given the potential of life history approaches to provide a powerful theoretical framework for understanding human health and behaviour, I then recommend productive ways forward for the field: 1) greater focus on the life history trade-offs which underlie proposed strategies; 2) greater precision when using the language of life history theory and life history strategies; 3) collecting more empirical data, from a diverse range of populations, on linkages between life history traits, behavioural traits and the environment, including the underlying mechanisms which generate these linkages; and 4) greater integration with the social and health sciences.     

Do host bark traits influence trunk epiphyte communities?

Host bark traits are known to affect the characteristics of epiphyte communities in forests worldwide; however, few investigations of such relationships have been undertaken in New Zealand forests. By examining the trunk epiphyte communities on four co-occurring forest tree species (Agathis australis, Dacrydium cupressinum, Knightia excelsa and Vitex lucens) representing a range of bark characteristics, we sought evidence that bark traits may shape these communities. Sampling was conducted on tree trunks in the Waitakere and Hunua ranges in the Auckland Region. As expected, the rough but lightly shedding bark of Vitex lucens was found to support many epiphytes, whereas the coarsely flaking bark surface of Dacrydium cupressinum supported few epiphytes. Conversely, despite bark with a smooth texture that sheds in large flakes, and contrary to the suggestions of previous authors, Agathis australis trunks were found to support the greatest numbers of epiphytes and this species was one of the most frequent epiphyte hosts. The individual epiphytes found on Agathis australis, however, were significantly smaller and more appressed to the trunk than those on the other trees, and species composition differed from the other host species.