Degenerate Tetraploidy Was Established Before Bdelloid Rotifer Families Diverged

Rotifers of Class Bdelloidea are abundant freshwater invertebrates known for their remarkable ability to survive desiccation and their lack of males and meiosis. Sequencing and annotation of approximately 50-kb regions containing the four hsp82 heat shock genes of the bdelloid Philodina roseola, each located on a separate chromosome, have suggested that its genome is that of a degenerate tetraploid. In order to determine whether a similar structure exists in a bdelloid distantly related to P. roseola and if degenerate tetraploidy was established before the two species separated, we sequenced regions containing the hsp82 genes of a bdelloid belonging to a different family, Adineta vaga, and the histone gene clusters of P. roseola and A. vaga. Our findings are entirely consistent with degenerate tetraploidy and show that it was established before the two bdelloid families diverged and therefore probably before the bdelloid radiation.Molecular and Cellular BiologyOrganismic and Evolutionary Biolog

A holistic measurement model of movement competency in children

Different countries have different methods for assessing movement competence in children; however, it is unclear whether the test batteries that are used measure the same aspects of movement competence. The aim of this paper was to (1) investigate whether the Test of Gross Motor Development (TGMD-2) and Körperkoordinations Test für Kinder (KTK) measure the same aspects of children’s movement competence and (2) examine the factorial structure of the TGMD-2 and KTK in a sample of Australian children. A total of 158 children participated (M age = 9.5; SD = 2.2). First, confirmatory factor analysis examined the independent factorial structure of the KTK and TGMD-2. Second, it was investigated whether locomotor, object control and body coordination loaded on the latent variable Movement Competency. Confirmatory factor analysis indicated an adequate fit for both the KTK and TGMD-2. An adequate fit was also achieved for the final model. In this model, locomotor (r = .86), object control (r = .71) and body coordination (r = .52) loaded on movement competence. Findings support our hypothesis that the TGMD-2 and KTK measure discrete aspects of movement competence. Future researchers and practitioners should consider using a wider range of test batteries to assess movement competence

Definitions, Foundations and Associations of Physical Literacy: A Systematic Review

Background: The concept of physical literacy has stimulated increased research attention in recent years—being deployed in physical education, sport participation, and the promotion of physical activity. Independent research groups currently operationalize the construct differently. Objective The purpose of this systematic review was to conduct a systematic review of the physical literacy construct,as reflected in contemporary research literature. Methods: Five databases were searched using the preferred reporting items for systematic reviews and meta-analyses (PRISMA) guidelines for systematic reviews. Inclusion criteria were English language, peer reviewed, published by March 2016, and seeking to conceptualize physical literacy. Articles that met these criteria were analysed in relation to three core areas: properties/attributes, philosophicalfoundations and theoretical associations with other constructs. A total of 50 published articles met the inclusion criteria and were analysed qualitatively using inductive thematic analysis.Results: The thematic analysis addressed the three core areas. Under definitions, core attributes that define physical literacy were identified, as well as areas of conflict between different approaches currently being adopted. One relatively clear philosophical approach was prominent in approximately half of the papers, based on a monist/holistic ontology and phenomenological epistemology. Finally, theanalysis identified a number of theoretical associations, including health, physical activity and academic performance.Conclusions: Current literature contains different representations of the physical literacy construct. The costs and benefits of adopting an exclusive approach versus pluralism are considered. Recommendations for both researchers and practitioners focus on identifying and clearly articulating the definitions, philosophical assumptions and expected outcomes prior to evaluating the effectiveness of this emerging concept

Phylogenomics of Unusual Histone H2A Variants in Bdelloid Rotifers

Rotifers of Class Bdelloidea are remarkable in having evolved for millions of years, apparently without males and meiosis. In addition, they are unusually resistant to desiccation and ionizing radiation and are able to repair hundreds of radiation-induced DNA double-strand breaks per genome with little effect on viability or reproduction. Because specific histone H2A variants are involved in DSB repair and certain meiotic processes in other eukaryotes, we investigated the histone H2A genes and proteins of two bdelloid species. Genomic libraries were built and probed to identify histone H2A genes in Adineta vaga and Philodina roseola, species representing two different bdelloid families. The expressed H2A proteins were visualized on SDS-PAGE gels and identified by tandem mass spectrometry. We find that neither the core histone H2A, present in nearly all other eukaryotes, nor the H2AX variant, a ubiquitous component of the eukaryotic DSB repair machinery, are present in bdelloid rotifers. Instead, they are replaced by unusual histone H2A variants of higher mass. In contrast, a species of rotifer belonging to the facultatively sexual, desiccation- and radiation-intolerant sister class of bdelloid rotifers, the monogononts, contains a canonical core histone H2A and appears to lack the bdelloid H2A variant genes. Applying phylogenetic tools, we demonstrate that the bdelloid-specific H2A variants arose as distinct lineages from canonical H2A separate from those leading to the H2AX and H2AZ variants. The replacement of core H2A and H2AX in bdelloid rotifers by previously uncharacterized H2A variants with extended carboxy-terminal tails is further evidence for evolutionary diversity within this class of histone H2A genes and may represent adaptation to unusual features specific to bdelloid rotifers