Three‐spined sticklebacks Gasterosteus aculeatus as a model for exploring behavioural biology

Niko Tinbergen chose the three‐spined stickleback Gasterosteus aculeatus for his classic behavioural studies because they are small, robust, common and easy to house in the laboratory under reasonably natural conditions and also because their behaviour, while sufficiently simple to be tractable, is still sufficiently complex to be interesting. An analysis of citation records shows that this was an inspired choice. Research on these small fish has addressed all four of Tinbergen's famous questions (causation, development, functions and evolution) and has contributed to the understanding of many different behavioural systems. The G. aculeatus literature is used here to explore several themes in fundamental behavioural biology (diet choice, shoaling, behavioural syndromes and sexual signalling) and the extent to which research using G. aculeatus has informed both fundamental and applied behavioural biology, the latter in the context of aquaculture research.     

Towards Transgenic Primates: What can we learn from mouse genetics?

Considering the great physiological and behavioral similarities with humans, monkeys represent the ideal models not only for the study of complex cognitive behavior but also for the preclinical research and development of novel therapeutics for treating human diseases. Various powerful genetic technologies initially developed for making mouse models are being explored for generating transgenic primate models. We review the latest genetic engineering technologies and discuss the potentials and limitations for systematic production of transgenic primates. Supported by Funding from GRA, NIMH and NIA.     

Transgenic barley (Hordeum vulgare L.) expressing the wheat aluminium resistance gene (TaALMT1) shows enhanced phosphorus nutrition and grain production when grown on an acid soil

Barley ( Hordeum vulgare L.), genetically modified with the Al³⁺ resistance gene of wheat ( TaALMT1 ), was compared with a non-transformed sibling line when grown on an acidic and highly phosphate-fixing ferrosol supplied with a range of phosphorus concentrations. In short-term pot trials (26 days), transgenic barley expressing TaALMT1 (GP-ALMT1) was more efficient than a non-transformed sibling line (GP) at taking up phosphorus on acid soil, but the genotypes did not differ when the soil was limed. Differences in phosphorus uptake efficiency on acid soil could be attributed not only to the differential effects of aluminium toxicity on root growth between the genotypes, but also to differences in phosphorus uptake per unit root length. Although GP-ALMT1 out-performed GP on acid soil, it was still not as efficient at taking up phosphorus as plants grown on limed soil. GP-ALMT1 plants grown in acid soil possessed substantially smaller rhizosheaths than those grown in limed soil, suggesting that root hairs were shorter. This is a probable reason for the lower phosphorus uptake efficiency. When grown to maturity in large pots, GP-ALMT1 plants produced more than twice the grain as GP plants grown on acid soil and 80% of the grain produced by limed controls. Expression of TaALMT1 in barley was not associated with a penalty in either total shoot or grain production in the absence of Al³⁺, with both genotypes showing equivalent yields in limed soil. These findings demonstrate that an important crop species can be genetically engineered to successfully increase grain production on an acid soil.     

Assessing what is needed to resolve a molecular phylogeny: simulations and empirical data from emydid turtles

Background  

Section Calochroi is one of the most species-rich lineages in the genus Cortinarius (Agaricales, Basidiomycota) and is widely distributed across boreo-nemoral areas, with some extensions into meridional zones. Previous phylogenetic studies of Calochroi (incl. section Fulvi) have been geographically restricted; therefore, phylogenetic and biogeographic relationships within this lineage at a global scale have been largely unknown. In this study, we obtained DNA sequences from a nearly complete taxon sampling of known species from Europe, Central America and North America. We inferred intra- and interspecific phylogenetic relationships as well as major morphological evolutionary trends within section Calochroi based on 576 ITS sequences, 230 ITS + 5.8S + D1/D2 sequences, and a combined dataset of ITS + 5.8S + D1/D2 and RPB1 sequences of a representative subsampling of 58 species.     

Assessing statistical power of SNPs for population structure and conservation studies

Single nucleotide polymorphisms (SNPs) have been proposed by some as the new frontier for population studies, and several papers have presented theoretical and empirical evidence reporting the advantages and limitations of SNPs. As a practical matter, however, it remains unclear how many SNP markers will be required or what the optimal characteristics of those markers should be in order to obtain sufficient statistical power to detect different levels of population differentiation. We use a hypothetical case to illustrate the process of designing a population genetics project, and present results from simulations that address several issues for maximizing statistical power to detect differentiation while minimizing the amount of effort in developing SNPs. Results indicate that (i) while ~30 SNPs should be sufficient to detect moderate (F_ST = 0.01) levels of differentiation, studies aimed at detecting demographic independence (e.g. F_ST < 0.005) may require 80 or more SNPs and large sample sizes; (ii) different SNP allele frequencies have little affect on power, and thus, selection of SNPs can be relatively unbiased; (iii) increasing the sample size has a strong effect on power, so that the number of loci can be minimized when sample number is known, and increasing sample size is almost always beneficial; and (iv) power is increased by including multiple SNPs within loci and inferring haplotypes, rather than trying to use only unlinked SNPs. This also has the practical benefit of reducing the SNP ascertainment effort, and may influence the decision of whether to seek SNPs in coding or noncoding regions.     

A panel of microsatellite loci from two species of octopus, Pareledone turqueti (Joubin, 1905) and Pareledone charcoti (Joubin, 1905)

Eighteen dinucleotide microsatellite loci were isolated from two octopus species, Pareledone turqueti and Pareledone charcoti, which are endemic to the Southern Ocean. Genetic diversity was assessed in samples of P. charcoti and P. turqueti from Elephant Island and Shag Rocks respectively. All except one locus (which has proved to be polymorphic in other species) were variable in the focal species and amplified between six and 30 and between four and 28 alleles for P. charcoti and P. turqueti respectively; mean expected heterozygosities varied between 0.38 and 0.95 (P. charcoti) and between 0.34 and 0.97 (P. turqueti), with significant (P < 0.05) departures from Hardy–Weinberg equilibrium at seven loci; three of these loci provided significant (P < 0.05) evidence for null alleles. Two pairs of loci isolated from P. turqueti demonstrated significant (P < 0.05) linkage disequilibrium. We are presently using these genetic markers to quantify spatial genetic structure in the genus Pareledone.     

Estimating Mass Properties of Dinosaurs Using Laser Imaging and 3D Computer Modelling

Body mass reconstructions of extinct vertebrates are most robust when complete to near-complete skeletons allow the reconstruction of either physical or digital models. Digital models are most efficient in terms of time and cost, and provide the facility to infinitely modify model properties non-destructively, such that sensitivity analyses can be conducted to quantify the effect of the many unknown parameters involved in reconstructions of extinct animals. In this study we use laser scanning (LiDAR) and computer modelling methods to create a range of 3D mass models of five specimens of non-avian dinosaur; two near-complete specimens of Tyrannosaurus rex, the most complete specimens of Acrocanthosaurus atokensis and Strutiomimum sedens, and a near-complete skeleton of a sub-adult Edmontosaurus annectens. LiDAR scanning allows a full mounted skeleton to be imaged resulting in a detailed 3D model in which each bone retains its spatial position and articulation. This provides a high resolution skeletal framework around which the body cavity and internal organs such as lungs and air sacs can be reconstructed. This has allowed calculation of body segment masses, centres of mass and moments or inertia for each animal. However, any soft tissue reconstruction of an extinct taxon inevitably represents a best estimate model with an unknown level of accuracy. We have therefore conducted an extensive sensitivity analysis in which the volumes of body segments and respiratory organs were varied in an attempt to constrain the likely maximum plausible range of mass parameters for each animal. Our results provide wide ranges in actual mass and inertial values, emphasizing the high level of uncertainty inevitable in such reconstructions. However, our sensitivity analysis consistently places the centre of mass well below and in front of hip joint in each animal, regardless of the chosen combination of body and respiratory structure volumes. These results emphasize that future biomechanical assessments of extinct taxa should be preceded by a detailed investigation of the plausible range of mass properties, in which sensitivity analyses are used to identify a suite of possible values to be tested as inputs in analytical models.