Diversification across an altitudinal gradient in the Tiny Greenbul (Phyllastrephus debilis) from the Eastern Arc Mountains of Africa

<p>Abstract</p> <p>Background</p> <p>The Eastern Arc Mountains of Africa have become one of the focal systems with which to explore the patterns and mechanisms of diversification among montane species and populations. One unresolved question is the extent to which populations inhabiting montane forest interact with those of adjacent lowland forest abutting the coast of eastern Africa. The Tiny Greenbul (<it>Phyllastephus debilis</it>) represents the only described bird species within the Eastern Arc/coastal forest mosaic, which is polytypic across an altitudinal gradient: the subspecies <it>albigula </it>(green head) is distributed in the montane Usambara and Nguru Mountains whereas the subspecies <it>rabai </it>(grey head) is found in Tanzanian lowland and foothill forest. Using a combination of morphological and genetic data, we aim to establish if the pattern of morphological differentiation in the Tiny Greenbul (<it>Phyllastrephus debilis</it>) is the result of disruptive selection along an altitudinal gradient or a consequence of secondary contact following population expansion of two differentiated lineages.</p> <p>Results</p> <p>We found significant biometric differences between the lowland (<it>rabai</it>) and montane (<it>albigula</it>) populations in Tanzania. The differences in shape are coupled with discrete differences in the coloration of the underparts. Using multi-locus data gathered from 124 individuals, we show that lowland and montane birds form two distinct genetic lineages. The divergence between the two forms occurred between 2.4 and 3.1 Myrs ago.</p> <p>Our coalescent analyses suggest that limited gene flow, mostly from the subspecies <it>rabai </it>to <it>albigula</it>, is taking place at three mid-altitude localities, where lowland and montane rainforest directly abut. The extent of this introgression appears to be limited and is likely a consequence of the recent expansion of <it>rabai </it>further inland.</p> <p>Conclusion</p> <p>The clear altitudinal segregation in morphology found within the Tiny Greenbul is the result of secondary contact of two highly differentiated lineages rather than disruptive selection in plumage pattern across an altitudinal gradient. Based on our results, we recommend <it>albigula </it>be elevated to species rank.</p

Somatosensory processing in neurodevelopmental disorders

The purpose of this article is to review the role of somatosensory perception in typical development, its aberration in a range of neurodevelopmental disorders, and the potential relations between tactile processing abnormalities and central features of each disorder such as motor, communication, and social development. Neurodevelopmental disorders that represent a range of symptoms and etiologies, and for which multiple peer-reviewed articles on somatosensory differences have been published, were chosen to include in the review. Relevant studies in animal models, as well as conditions of early sensory deprivation, are also included. Somatosensory processing plays an important, yet often overlooked, role in typical development and is aberrant in various neurodevelopmental disorders. This is demonstrated in studies of behavior, sensory thresholds, neuroanatomy, and neurophysiology in samples of children with Fragile X syndrome, autism spectrum disorders (ASD), attention deficit hyperactivity disorder (ADHD), and cerebral palsy (CP). Impaired somatosensory processing is found in a range of neurodevelopmental disorders and is associated with deficits in communication, motor ability, and social skills in these disorders. Given the central role of touch in early development, both experimental and clinical approaches should take into consideration the role of somatosensory processing in the etiology and treatment of neurodevelopmental disorders

Guidelines for the use and interpretation of assays for monitoring autophagy (4th edition)1.

In 2008, we published the first set of guidelines for standardizing research in autophagy. Since then, this topic has received increasing attention, and many scientists have entered the field. Our knowledge base and relevant new technologies have also been expanding. Thus, it is important to formulate on a regular basis updated guidelines for monitoring autophagy in different organisms. Despite numerous reviews, there continues to be confusion regarding acceptable methods to evaluate autophagy, especially in multicellular eukaryotes. Here, we present a set of guidelines for investigators to select and interpret methods to examine autophagy and related processes, and for reviewers to provide realistic and reasonable critiques of reports that are focused on these processes. These guidelines are not meant to be a dogmatic set of rules, because the appropriateness of any assay largely depends on the question being asked and the system being used. Moreover, no individual assay is perfect for every situation, calling for the use of multiple techniques to properly monitor autophagy in each experimental setting. Finally, several core components of the autophagy machinery have been implicated in distinct autophagic processes (canonical and noncanonical autophagy), implying that genetic approaches to block autophagy should rely on targeting two or more autophagy-related genes that ideally participate in distinct steps of the pathway. Along similar lines, because multiple proteins involved in autophagy also regulate other cellular pathways including apoptosis, not all of them can be used as a specific marker for bona fide autophagic responses. Here, we critically discuss current methods of assessing autophagy and the information they can, or cannot, provide. Our ultimate goal is to encourage intellectual and technical innovation in the field

Unions, worker voice, and management practices: Implications for a high-productivity, high-wage economy

© 2019 Russell Sage Foundation. This article uses the metaphor of a social contract to review the evolution of American unions and their effects - especially in the variations in their quality - on firm employment strategies and performance, takes stock of the current state of unions and alternative forms of worker voice that have emerged in recent years, and discusses implications for the future of labor and employment policies. The key policy implication is that fundamental, not incremental, changes in labor policy will be needed if the range of worker voice and representation processes workers want and the economy needs are to grow to a scale large enough to close existing voice gaps and contribute to building a new productivity- and wage-enhancing social contract