The functional traits of host fish can act as good predictors for parasite composition in a neotropical floodplain

Parasite diversity can be influenced by the interaction of environmental factors and host traits, but understanding which traits can be decisive for the establishment of the parasite may provide subsidies for a better understanding of the host-parasite relationship. In this study, we investigated whether functional traits, diet, and host phylogeny can predict the similarity of the endoparasite composition of a fish assemblage in a Brazilian floodplain. Of the three evaluated components, the host's diet was the factor that showed the greatest influence on the composition and similarity of endoparasites, demonstrating the highest value of the explanation. The functional traits and phylogeny, despite presenting significant values (unique effect and global effect), showed low explainability in the composition of the endoparasites. When analyzing the joint effects, all components showed significant influence. Hosts that live in the same environment that are phylogenetically related and have a similar ecology have a certain degree of homogeneity in their parasite assemblages and, because they are endoparasites (which are acquired trophically along the chain), diet is the main driver of parasite richness and similarity. Overall, host traits can be one of the main determinants of parasite composition, so studies that address the functional traits of the host provide a representation of local diversity and define the possible patterns of these parasite communities.     

中国鲤形目鱼类的中轴骨骼数及其生态适应性

为探讨中国鲤形目鱼类中轴骨骼数及其与系统发育和生态习性的相关性,采用X光透视照相法对157种鲤科(Cyprinidae)、鳅科(Cobitidae)、平鳍鳅科(Balitoridae)鱼类的脊椎骨数、肋骨数、尾椎数进行了比较分析。结果显示,中国鲤形目鱼类的脊椎骨数在30-52枚之间,均值39.45?4.44;肋骨数在8-28对之间,均值15.27?3.08;尾椎数在14-34枚之间,均值21.08?2.89。依据脊椎骨数、肋骨数、尾椎数对鲤科各亚科进行聚类,显示鲤科12个亚科分为2大类：雅罗鱼类,包括雅罗鱼亚科、鲌亚科、鲴亚科、裂腹鱼亚科等4亚科;鲃类,包括鲢亚科、鮈亚科、鱼丹亚科、鲃亚科、野鲮亚科、鳅鮀亚科、鲤亚科、鱊亚科等8亚科。单因素方差分析显示,鲤科肉食性鱼类的肋骨数与脊椎骨数的比值显著少于植食性鱼类(P＜0.05),而脊椎骨数、尾椎数则显著多于植食性鱼类(P＜0.05)。中上层鱼类的脊椎骨数、尾椎数显著多于下层鱼类(P＜0.05)。极小型鱼类的脊椎骨数、肋骨数,以及肋骨数与脊椎骨数之比显著少于大型鱼类(P＜0.05)。表明鲤科鱼类的中轴骨骼数与其系统发育和生态习性及体型具有明显的相关性。     

极小种群野生植物的近地保护

低于最小存活种群（Minimum Viable Population,简称：MVP）界线而濒临灭绝的极小种群野生植物是需要最优先保护的物种。“近地保护”是云南省林业厅在近年提出的对极小种群野生植物进行保护的一种新方法,它已成为国家林业局的野生植物六大拯救措施之一。根据近年来云南省对极小种群野生植物近地保护的实践和所取得的成果,以及经笔者对若干种国家重点保护植物在迁地保护与就地保护条件下的生长与适应性的比较研究,认为对包括极小种群在内的受严重威胁植物的近地保护的有效性远高于对它们的迁地保护。因而,笔者建议,应该尽快建立和完善野生植物近地保护体系,进一步加强极小种群野生植物高风险灭绝机制的研究,才能有的放矢地选择恰当的保护方法和科学的措施,以及在近地保护的实践中还必须遵循气候相似、生境相似和群落相似的生态学原则,以减少投入和提高其保护的有效性。     

Associations between single nucleotide polymorphisms in 33 candidate genes and meat quality traits in commercial pigs

This study aimed to evaluate the effects of single nucleotide polymorphisms (SNPs) in candidate genes for meat quality using a custom 96‐SNP panel (Illumina Vera Code GoldenGate Assay) on 15 traits collected from 400 commercial pigs. Meat quality measurements included muscle pH, color (L*, a* and b*), drip loss, cooking loss, peak shear force and six sensory traits including appearance (outside and inside), tenderness, juiciness, flavor and overall liking as well as carcass weight and probe yield. Thirty‐five SNPs with minor allele frequencies > 0.10 remained for the multimarker association using the GLM procedure of sas 9.2. Results showed that 20 SNPs were significantly associated with at least one of the traits with either additive or dominance or both effects (P < 0.05). Among these significant SNPs, five of them in ADIPOQ, FTO, TNF, LEPR and AMPD1 had an effect on more than three traits simultaneously; those in MC4R, CAST, DGAT1 and MYF6 had an effect on two traits, while the others were associated with one trait. The results suggest that these markers could be incorporated into commercial pigs for marker‐assisted selection and breeding programs for carcass and meat quality trait improvement.     

A selection strategy in plant transformation based on antisense oligodeoxynucleotide inhibition

Antisense oligodeoxynucleotide (asODN) inhibition was developed in the 1970s, and since then has been widely used in animal research. However, in plant biology, the method has had limited application because plant cell walls significantly block efficient uptake of asODN to plant cells. Recently, we have found that asODN uptake is enhanced in a sugar solution. The method has promise for many applications, such as a rapid alternative to time‐consuming transgenic studies, and high potential for studying gene functionality in intact plants and multiple plant species, with particular advantages in evaluating the roles of multiple gene family members. Generation of transgenic plants relies on the ability to select transformed cells. This screening process is based on co‐introduction of marker genes into the plant cell together with a gene of interest. Currently, the most common marker genes are those that confer antibiotic or herbicide resistance. The possibility that traits introduced by selectable marker genes in transgenic field crops may be transferred horizontally is of major public concern. Marker genes that increase use of antibiotics and herbicides may increase development of antibiotic‐resistant bacterial strains or contribute to weed resistance. Here, we describe a method for selection of transformed plant cells based on asODN inhibition. The method enables selective and high‐throughput screening for transformed cells without conferring new traits or functions to the transgenic plants. Due to their high binding specificity, asODNs may also find applications as plant‐specific DNA herbicides.     

Commentary on Ditch,Stitch and Pitch: the niche is here to stay

A recent set of discussion papers in the Journal of Biogeography by McInerny and Etienne (henceforth M&E) questions the value of niche concepts in relation to a diverse group of practices collectively labelled species distribution modelling (SDM), and specifically the usefulness of the idea of a fundamental niche. In this Correspondence, I argue that certain types of SDM may indeed dispense with niche concepts, but that such is not the case for an important class of SDM‐based activities, including transferring predictions in space and time. Using a single term (SDM) to denote diverse objectives and practices does not help to clarify issues; I discuss this point. I also review several criticisms raised by M&E about the use of the concept of fundamental niche in the context of modelling species' distributions and their environments.     

Heritability and quantitative genetic divergence of serotiny,a fire-persistence plant trait

Background and Aims

Although it is well known that fire acts as a selective pressure shaping plant phenotypes, there are no quantitative estimates of the heritability of any trait related to plant persistence under recurrent fires, such as serotiny. In this study, the heritability of serotiny in Pinus halepensis is calculated, and an evaluation is made as to whether fire has left a selection signature on the level of serotiny among populations by comparing the genetic divergence of serotiny with the expected divergence of neutral molecular markers (Q_ST–F_ST comparison).

Methods

A common garden of P. halepensis was used, located in inland Spain and composed of 145 open-pollinated families from 29 provenances covering the entire natural range of P. halepensis in the Iberian Peninsula and Balearic Islands. Narrow-sense heritability (h²) and quantitative genetic differentiation among populations for serotiny (Q_ST) were estimated by means of an ‘animal model’ fitted by Bayesian inference. In order to determine whether genetic differentiation for serotiny is the result of differential natural selection, Q_ST estimates for serotiny were compared with F_ST estimates obtained from allozyme data. Finally, a test was made of whether levels of serotiny in the different provenances were related to different fire regimes, using summer rainfall as a proxy for fire regime in each provenance.

Key Results

Serotiny showed a significant narrow-sense heritability (h²) of 0·20 (credible interval 0·09–0·40). Quantitative genetic differentiation among provenances for serotiny (Q_ST = 0·44) was significantly higher than expected under a neutral process (F_ST = 0·12), suggesting adaptive differentiation. A significant negative relationship was found between the serotiny level of trees in the common garden and summer rainfall of their provenance sites.

Conclusions

Serotiny is a heritable trait in P. halepensis, and selection acts on it, giving rise to contrasting serotiny levels among populations depending on the fire regime, and supporting the role of fire in generating genetic divergence for adaptive traits.     

The effect of drought stress on heterozygosity–fitness correlations in pedunculate oak (Quercus robur)

Background and Aims

The interaction between forest fragmentation and predicted climate change may pose a serious threat to tree populations. In small and spatially isolated forest fragments, increased homozygosity may directly affect individual tree fitness through the expression of deleterious alleles. Climate change-induced drought stress may exacerbate these detrimental genetic consequences of forest fragmentation, as the fitness response to low levels of individual heterozygosity is generally thought to be stronger under environmental stress than under optimal conditions.

Methods

To test this hypothesis, a greenhouse experiment was performed in which various transpiration and growth traits of 6-month-old seedlings of Quercus robur differing in multilocus heterozygosity (MLH) were recorded for 3 months under a well-watered and a drought stress treatment. Heterozygosity–fitness correlations (HFC) were examined by correlating the recorded traits of individual seedlings to their MLH and by studying their response to drought stress.

Key Results

Weak, but significant, effects of MLH on several fitness traits were obtained, which were stronger for transpiration variables than for the recorded growth traits. High atmospheric stress (measured as vapour pressure deficit) influenced the strength of the HFCs of the transpiration variables, whereas only a limited effect of the irrigation treatment on the HFCs was observed.

Conclusions

Under ongoing climate change, increased atmospheric stress in the future may strengthen the negative fitness responses of trees to low MLH. This indicates the necessity to maximize individual multilocus heterozygosity in forest tree breeding programmes.     

Diversification and the evolution of dispersal ability in the tribe Brassiceae (Brassicaceae)

MethodsThe phylogenetic analysis included 72 taxa sampled from across the Brassiceae and included both nuclear and chloroplast markers. Dispersal-related fruit characters were scored and climate information for each taxon was retrieved from a database. Correlations between fruit traits, seed characters, habitat, range and climate were determined, together with trait-dependent diversification rates.ConclusionsThis study provides evidence that the evolution of increased dispersal ability and larger seed size, which may increase establishment ability, can also influence macro-evolutionary processes, possibly by increasing the propensity for long-distance dispersal. In particular, it may increase speciation and consequent diversification rates by increasing the likelihood of geographic and thereby reproductive isolation.