TY - JOUR AB - Sexual dimorphism in morphology, physiology or life history traits is common in dioecious plants at reproductive maturity, but it is typically inconspicuous or absent in juveniles. Although plants of different sexes probably begin to diverge in gene expression both before their reproduction commences and before dimorphism becomes readily apparent, to our knowledge transcriptome-wide differential gene expression has yet to be demonstrated for any angiosperm species. AU - Cossard, Guillaume AU - Toups, Melissa A AU - Pannell, John ID - 6710 IS - 7 JF - Annals of botany SN - 0305-7364 TI - Sexual dimorphism and rapid turnover in gene expression in pre-reproductive seedlings of a dioecious herb VL - 123 ER - TY - GEN AB - Evolutionary studies are often limited by missing data that are critical to understanding the history of selection. Selection experiments, which reproduce rapid evolution under controlled conditions, are excellent tools to study how genomes evolve under selection. Here we present a genomic dissection of the Longshanks selection experiment, in which mice were selectively bred over 20 generations for longer tibiae relative to body mass, resulting in 13% longer tibiae in two replicates. We synthesized evolutionary theory, genome sequences and molecular genetics to understand the selection response and found that it involved both polygenic adaptation and discrete loci of major effect, with the strongest loci tending to be selected in parallel between replicates. We show that selection may favor de-repression of bone growth through inactivating two limb enhancers of an inhibitor, Nkx3-2. Our integrative genomic analyses thus show that it is possible to connect individual base-pair changes to the overall selection response. AU - Castro, João Pl AU - Yancoskie, Michelle N. AU - Marchini, Marta AU - Belohlavy, Stefanie AU - Hiramatsu, Layla AU - Kučka, Marek AU - Beluch, William H. AU - Naumann, Ronald AU - Skuplik, Isabella AU - Cobb, John AU - Barton, Nicholas H AU - Rolian, Campbell AU - Chan, Yingguang Frank ID - 9804 TI - Data from: An integrative genomic analysis of the Longshanks selection experiment for longer limbs in mice ER - TY - GEN AB - This paper analyzes how partial selfing in a large source population influences its ability to colonize a new habitat via the introduction of a few founder individuals. Founders experience inbreeding depression due to partially recessive deleterious alleles as well as maladaptation to the new environment due to selection on a large number of additive loci. I first introduce a simplified version of the Inbreeding History Model (Kelly, 2007) in order to characterize mutation-selection balance in a large, partially selfing source population under selection involving multiple non-identical loci. I then use individual-based simulations to study the eco-evolutionary dynamics of founders establishing in the new habitat under a model of hard selection. The study explores how selfing rate shapes establishment probabilities of founders via effects on both inbreeding depression and adaptability to the new environment, and also distinguishes the effects of selfing on the initial fitness of founders from its effects on the long-term adaptive response of the populations they found. A high rate of (but not complete) selfing is found to aid establishment over a wide range of parameters, even in the absence of mate limitation. The sensitivity of the results to assumptions about the nature of polygenic selection are discussed. AU - Sachdeva, Himani ID - 9802 TI - Data from: Effect of partial selfing and polygenic selection on establishment in a new habitat ER - TY - JOUR AB - We study the topology generated by the temperature fluctuations of the cosmic microwave background (CMB) radiation, as quantified by the number of components and holes, formally given by the Betti numbers, in the growing excursion sets. We compare CMB maps observed by the Planck satellite with a thousand simulated maps generated according to the ΛCDM paradigm with Gaussian distributed fluctuations. The comparison is multi-scale, being performed on a sequence of degraded maps with mean pixel separation ranging from 0.05 to 7.33°. The survey of the CMB over 𝕊2 is incomplete due to obfuscation effects by bright point sources and other extended foreground objects like our own galaxy. To deal with such situations, where analysis in the presence of “masks” is of importance, we introduce the concept of relative homology. The parametric χ2-test shows differences between observations and simulations, yielding p-values at percent to less than permil levels roughly between 2 and 7°, with the difference in the number of components and holes peaking at more than 3σ sporadically at these scales. The highest observed deviation between the observations and simulations for b0 and b1 is approximately between 3σ and 4σ at scales of 3–7°. There are reports of mildly unusual behaviour of the Euler characteristic at 3.66° in the literature, computed from independent measurements of the CMB temperature fluctuations by Planck’s predecessor, the Wilkinson Microwave Anisotropy Probe (WMAP) satellite. The mildly anomalous behaviour of the Euler characteristic is phenomenologically related to the strongly anomalous behaviour of components and holes, or the zeroth and first Betti numbers, respectively. Further, since these topological descriptors show consistent anomalous behaviour over independent measurements of Planck and WMAP, instrumental and systematic errors may be an unlikely source. These are also the scales at which the observed maps exhibit low variance compared to the simulations, and approximately the range of scales at which the power spectrum exhibits a dip with respect to the theoretical model. Non-parametric tests show even stronger differences at almost all scales. Crucially, Gaussian simulations based on power-spectrum matching the characteristics of the observed dipped power spectrum are not able to resolve the anomaly. Understanding the origin of the anomalies in the CMB, whether cosmological in nature or arising due to late-time effects, is an extremely challenging task. Regardless, beyond the trivial possibility that this may still be a manifestation of an extreme Gaussian case, these observations, along with the super-horizon scales involved, may motivate the study of primordial non-Gaussianity. Alternative scenarios worth exploring may be models with non-trivial topology, including topological defect models. AU - Pranav, Pratyush AU - Adler, Robert J. AU - Buchert, Thomas AU - Edelsbrunner, Herbert AU - Jones, Bernard J.T. AU - Schwartzman, Armin AU - Wagner, Hubert AU - Van De Weygaert, Rien ID - 6756 JF - Astronomy and Astrophysics SN - 00046361 TI - Unexpected topology of the temperature fluctuations in the cosmic microwave background VL - 627 ER - TY - JOUR AB - Differentiated sex chromosomes are accompanied by a difference in gene dose between X/Z-specific and autosomal genes. At the transcriptomic level, these sex-linked genes can lead to expression imbalance, or gene dosage can be compensated by epigenetic mechanisms and results into expression level equalization. Schistosoma mansoni has been previously described as a ZW species (i.e., female heterogamety, in opposition to XY male heterogametic species) with a partial dosage compensation, but underlying mechanisms are still unexplored. Here, we combine transcriptomic (RNA-Seq) and epigenetic data (ChIP-Seq against H3K4me3, H3K27me3,andH4K20me1histonemarks) in free larval cercariae and intravertebrate parasitic stages. For the first time, we describe differences in dosage compensation status in ZW females, depending on the parasitic status: free cercariae display global dosage compensation, whereas intravertebrate stages show a partial dosage compensation. We also highlight regional differences of gene expression along the Z chromosome in cercariae, but not in the intravertebrate stages. Finally, we feature a consistent permissive chromatin landscape of the Z chromosome in both sexes and stages. We argue that dosage compensation in schistosomes is characterized by chromatin remodeling mechanisms in the Z-specific region. AU - Picard, Marion A L AU - Vicoso, Beatriz AU - Roquis, David AU - Bulla, Ingo AU - Augusto, Ronaldo C. AU - Arancibia, Nathalie AU - Grunau, Christoph AU - Boissier, Jérôme AU - Cosseau, Céline ID - 6755 IS - 7 JF - Genome biology and evolution TI - Dosage compensation throughout the Schistosoma mansoni lifecycle: Specific chromatin landscape of the Z chromosome VL - 11 ER - TY - JOUR AB - Two-player games on graphs are widely studied in formal methods, as they model the interaction between a system and its environment. The game is played by moving a token throughout a graph to produce an infinite path. There are several common modes to determine how the players move the token through the graph; e.g., in turn-based games the players alternate turns in moving the token. We study the bidding mode of moving the token, which, to the best of our knowledge, has never been studied in infinite-duration games. The following bidding rule was previously defined and called Richman bidding. Both players have separate budgets, which sum up to 1. In each turn, a bidding takes place: Both players submit bids simultaneously, where a bid is legal if it does not exceed the available budget, and the higher bidder pays his bid to the other player and moves the token. The central question studied in bidding games is a necessary and sufficient initial budget for winning the game: a threshold budget in a vertex is a value t ∈ [0, 1] such that if Player 1’s budget exceeds t, he can win the game; and if Player 2’s budget exceeds 1 − t, he can win the game. Threshold budgets were previously shown to exist in every vertex of a reachability game, which have an interesting connection with random-turn games—a sub-class of simple stochastic games in which the player who moves is chosen randomly. We show the existence of threshold budgets for a qualitative class of infinite-duration games, namely parity games, and a quantitative class, namely mean-payoff games. The key component of the proof is a quantitative solution to strongly connected mean-payoff bidding games in which we extend the connection with random-turn games to these games, and construct explicit optimal strategies for both players. AU - Avni, Guy AU - Henzinger, Thomas A AU - Chonev, Ventsislav K ID - 6752 IS - 4 JF - Journal of the ACM SN - 00045411 TI - Infinite-duration bidding games VL - 66 ER - TY - CONF AB - Numerous biophysical questions require the quantification of short-range interactions between (functionalized) surfaces and synthetic or biological objects such as cells. Here, we present an original, custom built setup for reflection interference contrast microscopy that can assess distances between a substrate and a flowing object at high speed with nanometric accuracy. We demonstrate its use to decipher the complex biochemical and mechanical interplay regulating blood cell homing at the vessel wall in the microcirculation using an in vitro approach. We show that in the absence of specific biochemical interactions, flowing cells are repelled from the soft layer lining the vessel wall, contributing to red blood cell repulsion in vivo. In contrast, this so-called glycocalyx stabilizes rolling of cells under flow in the presence of a specific receptor naturally present on activated leucocytes and a number of cancer cell lines. AU - Davies, Heather S. AU - Baranova, Natalia S. AU - El Amri, Nouha AU - Coche-Guérente, Liliane AU - Verdier, Claude AU - Bureau, Lionel AU - Richter, Ralf P. AU - Débarre, Delphine ID - 7010 SN - 1605-7422 T2 - Advances in Microscopic Imaging II TI - Blood cell-vessel wall interactions probed by reflection interference contrast microscopy VL - 11076 ER - TY - JOUR AB - When grape-sized aqueous dimers are irradiated in a microwave oven, an intense electromagnetic hotspot forms at their point of contact, often igniting a plasma. Here we show that this irradiation can result in the injection of mechanical energy. By examining irradiated hydrogel dimers through high-speed imaging, we find that they repeatedly bounce off of each other while irradiated. We determine that an average of 1 lJ of mechanical energy is injected into the pair during each collision. Furthermore, a characteristic high-pitched audio signal is found to accompany each collision. We show that both the audio signal and the energy injection arise via an interplay between vaporization and elastic deformations in the region of contact, the so-called ‘elastic Liedenfrost effect’. Our results establish a novel, non-contact method of injecting mechanical energy into soft matter systems, suggesting application in fields such as soft robotics. AU - Khattak, Hamza K. AU - Waitukaitis, Scott R AU - Slepkov, Aaron D. ID - 6763 IS - 29 JF - Soft Matter SN - 1744683X TI - Microwave induced mechanical activation of hydrogel dimers VL - 15 ER - TY - JOUR AB - Mathematical models have been used successfully at diverse scales of biological organization, ranging from ecology and population dynamics to stochastic reaction events occurring between individual molecules in single cells. Generally, many biological processes unfold across multiple scales, with mutations being the best studied example of how stochasticity at the molecular scale can influence outcomes at the population scale. In many other contexts, however, an analogous link between micro- and macro-scale remains elusive, primarily due to the challenges involved in setting up and analyzing multi-scale models. Here, we employ such a model to investigate how stochasticity propagates from individual biochemical reaction events in the bacterial innate immune system to the ecology of bacteria and bacterial viruses. We show analytically how the dynamics of bacterial populations are shaped by the activities of immunity-conferring enzymes in single cells and how the ecological consequences imply optimal bacterial defense strategies against viruses. Our results suggest that bacterial populations in the presence of viruses can either optimize their initial growth rate or their population size, with the first strategy favoring simple immunity featuring a single restriction modification system and the second strategy favoring complex bacterial innate immunity featuring several simultaneously active restriction modification systems. AU - Ruess, Jakob AU - Pleska, Maros AU - Guet, Calin C AU - Tkačik, Gašper ID - 6784 IS - 7 JF - PLoS Computational Biology TI - Molecular noise of innate immunity shapes bacteria-phage ecologies VL - 15 ER - TY - JOUR AB - An important adaptation during colonization of land by plants is gravitropic growth of roots, which enabled roots to reach water and nutrients, and firmly anchor plants in the ground. Here we provide insights into the evolution of an efficient root gravitropic mechanism in the seed plants. Architectural innovation, with gravity perception constrained in the root tips along with a shootward transport route for the phytohormone auxin, appeared only upon the emergence of seed plants. Interspecies complementation and protein domain swapping revealed functional innovations within the PIN family of auxin transporters leading to the evolution of gravitropism-specific PINs. The unique apical/shootward subcellular localization of PIN proteins is the major evolutionary innovation that connected the anatomically separated sites of gravity perception and growth response via the mobile auxin signal. We conclude that the crucial anatomical and functional components emerged hand-in-hand to facilitate the evolution of fast gravitropic response, which is one of the major adaptations of seed plants to dry land. AU - Zhang, Yuzhou AU - Xiao, G AU - Wang, X AU - Zhang, Xixi AU - Friml, Jiří ID - 6778 JF - Nature Communications SN - 2041-1723 TI - Evolution of fast root gravitropism in seed plants VL - 10 ER -