Cytogenetic analysis of the Asian plethodontid salamander, Karsenia koreana: evidence for karyotypic conservation, chromosome repatterning, and genome size evolution

The Concept of Neuromuscular Repatterning in Dancers: A Systematic Review

Repatterning is a term that can be used in different fields, including genetics, molecular biology, neurology, psychology, or rehabilitation. Our aim is to identify the key concept of neuromuscular repatterning in somatic training programmes for dancers. A systematic search of eight databases was conducted using the PRISMA (Preferred Reporting Items for Systematic Review and Meta-Analysis) guidelines. The Quality Assessment Tool for Quantitative Studies and the Oxford Levels of Evidence scales were used. The search yielded 1218 results, of which 5 met the inclusion criteria. Five studies (n = 5) were related to psychosomatic health (n = 5), two studies highlighted integration and inter-articular connectivity in movement (n = 2), four studies investigated the neurological component of alignment and efficiency in dance practice (n = 4), and two studies investigated self-confidence (n = 2). Five studies (n = 5) used imagery based on the anatomical and physiological experience of body systems as the main analytical method. Four studies (n = 4) used developmental movement through Bartenieff fundamentals as the main technique for this methodology. Developmental movement and imagery are two methodologies strongly connected to the concept of neuromuscular repatterning in somatic training programmes for dancers. The acquisition of further quantitative experimental or quasi-experimental studies is warranted to better define the level of improvement or impact of neuromuscular repatterning in dancers.

Presence of sodefrin precursor-like factor pheromone candidates in mental and dorsal tail base glands in the plethodontid salamander, Karsenia koreana

Plethodontid salamanders are well known for their distinct courtship rituals and the associated pheromonal signaling. However, little is known about pheromones produced in the lone Asian plethodontid species Karsenia koreana. Here, we examined the localization patterns of proteins of the sodefrin precursor-like factor (SPF) pheromone system in K. koreana. Using an antibody generated against SPF proteins from another plethodontid, Desmognathus ocoee, we tested three types of skin glands in K. koreana males via immunohistochemistry: the mental gland and two types of dorsal tail base glands-caudal courtship glands and dorsal granular glands. SPF immunoreactivity was detected in the known courtship gland, the mental gland, as well as granular glands, but not in caudal courtship glands. Due to immunoreaction specificity, we hypothesize the proteins of the SPF system in K. koreana and D. ocoee are structurally and functionally related and are used as courtship pheromones in K. koreana. Also, we hypothesize that K. koreana males transmit SPF to the female during the tail-straddling walk via dorsal granular glands. Finally, K. koreana male caudal courtship glands may be producing SPF proteins that are not recognized by our SPF antibody or these glands may play a different role in courtship than anticipated.

The Asian plethodontid salamander preserves historical genetic imprints of recent northern expansion

The Korean Peninsula, located at the southern tip of Northeast Asia, has never been covered by ice sheets and was a temperate refugium during the Pleistocene. Karsenia koreana, the sole Asian plethodontid salamander species, occurs only on the southern half of the Korean Peninsula and is thought to have found various climatic refugia. Despite its phylogenetic and biogeographic importance, no population-level genetic analysis has been performed on this species. Here we study the population genetic structure of K. koreana using mitochondrial and microsatellite loci to understand the recent historical dispersion process that shaped its current distribution. Overall, the genetic distance between populations correlated well with the spatial distance, and the genetic structure among populations showed signs of a unilateral northward expansion from a southernmost refugium population. Given the distinct genetic structure formed among the populations, the level of historical gene flow among populations appears to have been very low. As the estimated effective population size of K. koreana was also small, these results suggest that the small, restricted populations of K. koreana are extremely vulnerable to environmental changes that may require high levels of genetic diversity to cope with. Thus, special management strategies are needed to preserve these remnant populations.

Climate change-based models predict range shifts in the distribution of the only Asian plethodontid salamander: Karsenia koreana

Populations see their range fluctuate in relation to environmental variations, including climate change, and their survival is linked to the maintenance of large enough populations and broad enough distributions during these variations. Most amphibian populations are threatened by numerous ecological and anthropogenic variables acting in synergy with climate change. Accumulating basic ecological data such as range enables the development of population and range dynamics, themselves resulting on adequate conservation plans. Karsenia koreana is the only known Asian plethodontic salamander, occurring in a very restricted area only. Based on presence data, we created an ecological model using six bioclimatic factors with low multicollinearity to define the adequate habitat of the species, and we modelled the predicted suitability of the Korean landscape following four Representative Concentration Pathways (RCPs) predicting climate change scenarios based on CO2 concentrations in 2050 and 2070. The maximum entropy model for the current distribution produced a landscape suitability considerably wider than the current known distribution. The projected ranges for each RCP indicated marked increases, decreases and shifts in areas with suitable landscapes due to climate change. The lowest RCP prediction resulted in an increase in suitable area, although potentially without connectivity with current populations, while the highest RCP predictions resulted in a decrease. Our results highlight the potential negative impact of climate change, thus requiring updates in conservation plans for K. koreana. The methods used here can be replicated with any land-dwelling species, and our results reflect expected range shifts for most amphibians of the northern hemisphere.

Proteomic and UTR analyses of a rapidly evolving hypervariable family of vertebrate pheromones

During the annual mating season, the mental gland of male plethodontid salamanders diverts its protein synthesizing capacity to the production of courtship pheromones that increase female receptivity. Plethodontid modulating factor (PMF), a highly disulfide-bonded 7-kDa pheromone, shows unusual hypervariability with each male expressing >30 isoforms. Twenty-eight PMFs were purified and matched by proteomic analyses to cDNA sequences. In contrast to coding sequence hypervariability, the untranslated regions (UTRs) show extraordinary conservation, no predicted microRNA binding sites, and an overlapping triplet polyadenylation signal. Full-length cDNA sequencing revealed three PMF gene classes containing subclasses of clustered sequences that support ≥ 13 PMF gene duplications. The unusual phenomena of hypervariable coding regions embedded within extremely conserved UTRs is proposed to occur by a disjunctive evolutionary process. During the short courtship season, the UTRs are hypothesized to subsume and coordinate the transcriptional and translational regulatory mechanisms of the mental gland. PMF, as a secreted protein with limited metabolic feedback in the male, is under minimal mutational restraint and thus has experienced highly accelerated rates of evolution. Consequently, plethodontid salamanders may provide a unique model for furthering our understanding of the selective forces that determine differential rates of gene duplication and evolution in protein families.

The New World Artemia species A. franciscana and A. persimilis are highly differentiated for chromosome size and heterochromatin content

Chromosomal rearrangements have played a key role in the speciation of the New World sexual Artemia species (Crustacea, Anostraca) A. franciscana and A. persimilis. The species differ by a chromosome duplication (2n+2=44 in A. persimilis vs 2n=42 in A. franciscana), and a greater amount of heterochromatin (HCH) in A. franciscana. To investigate this difference in HCH, four parameters were compared for the first time in Artemia: 1) the absolute sizes of one A. persimilis and four A. franciscana karyotypes; 2) the relative lengths of all chromosome; 3) the number of heterochromatic bands and 4) the relative amounts of HCH per chromosome and its position. The two A.franciscana karyotypes with the largest HCH amount (26%), have twice (139.26 microm and 134.05 microm) the absolute size of the A.persimilis karyotype (64.91 microm; HCH: 1.97%). Interspecific and intraspecific (A. franciscana) differences in chromosome size and HCH were observed, although the two sets of information are not positively correlated. While A. persimilis shares plesiomorphic karyological traits with Old World species, A. franciscana has apomorphic features such as longer chromosomes and greater HCH content, mainly dispersed towards telomeres. The impacts of such chromosome rearrangements are discussed in relation to the wider geographic distribution, greater colonizing ability, and life history plasticity of A. franciscana. An additional, though preliminary, point of this paper is the observation that the female would be the heterogametic sex.

Use of paleontological and molecular data in supertrees for comparative studies: the example of lissamphibian femoral microanatomy

A new method to assemble time-calibrated supertrees is able to incorporate paleontological and molecular dates. This method, along with new branch length transformations, is implemented in the Stratigraphic Tools for Mesquite. It was used here to analyse a dataset on bone microanatomy, body size and habitat of 46 species of lissamphibians through a variety of methods (Felsenstein independent contrasts, variance partition with phylogenetic eigenvector regression, discriminant analyses and simple regressions). Our analyses showed that the new methods can produce adequate standardization for several characters on a tree whose branch lengths can represent evolutionary time. The analyses confirmed previous conclusions about the presence of an ecological signal in bone microanatomical data.

Evolutionary cytogenetics in salamanders

Salamanders (Amphibia: Caudata/Urodela) have been the subject of numerous cytogenetic studies, and data on karyotypes and genome sizes are available for most groups. Salamanders show a more-or-less distinct dichotomy between families with large chromosome numbers and interspecific variation in chromosome number, relative size, and shape (i.e. position of the centromere), and those that exhibit very little variation in these karyological features. This dichotomy is the basis of a major model of karyotype evolution in salamanders involving a kind of 'karyotypic orthoselection'. Salamanders are also characterized by extremely large genomes (in terms of absolute mass of nuclear DNA) and extensive variation in genome size (and overall size of the chromosomes), which transcends variation in chromosome number and shape. The biological significance and evolution of chromosome number and shape within the karyotype is not yet understood, but genome size variation has been found to have strong phenotypic, biogeographic, and phylogenetic correlates that reveal information about the biological significance of this cytogenetic variable. Urodeles also present the advantage of only 10 families and less than 600 species, which facilitates the analysis of patterns within the entire order. The purpose of this review is to present a summary of what is currently known about overall patterns of variation in karyology and genome size in salamanders. These patterns are discussed within an evolutionary context.