Similar Evolutionary Paths Research Articles

Trace Element and Isotope Geochemistry of Tschicoma Formation Intermediate Composition Dome Complexes, Jemez Mountains Volcanic Field, New Mexico, USA

Abstract Repeated intrusions of mafic magma have long been known to be a driver of long-lived magmatic systems. Although the importance of mafic recharge of silicic magma systems is well-documented in igneous petrology, the origin of this recharge magma is sometimes obscure. By examining the pre-caldera intermediate dome complexes of the Tschicoma Formation and their relationship to a dacitic recharge event into the Tshirege Member of the Bandelier Tuff, we aim to better understand the origin of mafic recharge events into the Bandelier magma chamber of Valles caldera, and the relationship between different stages of volcanic activity within the broader Jemez Mountains volcanic field (JMVF). Based on major, trace element and radiogenic isotopic data, we divide the Tschicoma Formation into three geochemical groups with similar petrologic evolutionary paths. The Cerro Grande, Cerro Rubio and Pajarito Mountain volcanic dome complexes form group A and have assimilated various amounts of a granitoid crustal component with low εNd, εHf and radiogenic Pb. Group B consists of the Sawyer Dome, Rendija Canyon and Caballo Mountain dome complexes, which have principally evolved through different degrees of fractional crystallization of the same parent magma, itself a result of complex interactions of a mafic mantle-derived magma with the crust. The dacite domes and flows around Tschicoma Peak and the newly described Cañada Bonita dacite form group C and are the result of mixing of Rendija Canyon magma with mafic recharge magma which is preserved as distinct mafic enclaves. At a later stage of the JMVF, during the eruption of the Tshirege Member, distinctive hornblende–dacite pumices formed as a result of the influx of more mafic recharge magma into the system, which mobilized a pre-existing dacite intrusion and injected it into the Tshirege rhyolite ( Stimac, 1996; Boroet al.,2020). Based on trace element and isotopic compositions, we propose that dacite which was injected into the Tshirege magma chamber was related to the earlier-erupted Tschicoma Formation and itself represents a mixing product of Tshirege rhyolite and a precursor to the Tschicoma dacites. This implies that the Tschicoma magmatic system was long-lived yet dormant during the eruption of the Otowi Member of the Bandelier Tuff, then was reactivated shortly before the Tshirege eruption, temporarily co-existing and interacting with the Bandelier system as it erupted.

Morphological relationships among populations support a single taxonomic unit for the North American Gray Wolf

Abstract The Gray Wolf (Canis lupus) is viewed as one of the most diverse mammal species. In North America, the diversity of its forms is debated, with views conflicting on subspecies designation. The present study aimed to reinvestigate the skull morphometric variation among North American populations while attempting to unveil underlying causal factors. A large sample of vouchered museum skulls, collected from 12 ecogeographical populations spanning the North American range of the species, was examined and 21 craniodental characters were measured. Skull shape showed within-population variations but provided evidence for a high morphological affinity among populations. Allometric analyses also pointed to similar evolutionary paths among populations. However, significant size-related differentiation was revealed within and among populations. Skull size could be related to three insulin-like growth factor-1 gene (IGF-1) alleles. Ecological conditions that should determine prey type and availability accounted for most of the skull size variation. In contrast, no evidence of geographical isolation of populations was detected. The results support the existence of a single morphological pool of North American gray wolf populations that could be equated with one taxonomic unit. This study raises again the question of the diversity of forms in this species in North America and calls into question the validity of previously recognized species and subspecies based on genetics and morphology.

Epistasis, aneuploidy, and functional mutations underlie evolution of resistance to induced microtubule depolymerization.

Cells with blocked microtubule polymerization are delayed in mitosis, but eventually manage to proliferate despite substantial chromosome missegregation. While several studies have analyzed the first cell division after microtubule depolymerization, we have asked how cells cope long-term with microtubule impairment. We allowed 24 clonal populations of yeast cells with beta-tubulin mutations preventing proper microtubule polymerization, to evolve for ˜150 generations. At the end of the laboratory evolution experiment, cells had regained the ability to form microtubules and were less sensitive to microtubule-depolymerizing drugs. Whole-genome sequencing identified recurrently mutated genes, in particular for tubulins and kinesins, as well as pervasive duplication of chromosome VIII. Recreating these mutations and chromosome VIII disomy prior to evolution confirmed that they allow cells to compensate for the original mutation in beta-tubulin. Most of the identified mutations did not abolish function, but rather restored microtubule functionality. Analysis of the temporal order of resistance development in independent populations repeatedly revealed the same series of events: disomy of chromosome VIII followed by a single additional adaptive mutation in either tubulins or kinesins. Since tubulins are highly conserved among eukaryotes, our results have implications for understanding resistance to microtubule-targeting drugs widely used in cancer therapy.

Elucidation of environment dependent antibiotic resistance mechanisms

The propensity of pathogens to evolve resistance to antibiotics used in clinical infectious disease therapeutics has been an increasing concern in recent decades. Acquisition of resistance often translates into treatment failure and puts patients at risk of serious adverse outcomes. Current laboratory testing of antibiotic susceptibility does not account for the different microenvironments that bacteria encounter within the human body, providing results that often do not translate into the clinic. Our goal is to better understand evolutionary strategies employed by Staphylococcus aureus in development of resistance in distinct environments. We used adaptive laboratory evolution (ALE) to generate isogenic strains resistant to several antibiotics. Different media were used to mimic distinct environments and multi-omics approaches applied in the understanding of resistance mechanisms. Evolved strains presented phenotypes similar to those observed in clinical resistant isolates. Mutational analysis indicated that resistance was specific and condition-dependent. Distinct mutations led to resistance phenotypes under a particular environmental condition, but these mutations did not necessarily translate into resistance under a different environmental condition. Furthermore, resistant strains possessed distinct transcriptional landscapes, even when the same systems were mutated, suggesting that similar evolutionary paths translate into distinct resistance mechanisms. We identified several resistance mechanisms employed by S. aureus that were not only environment-dependent, but also environment specific. Additionally, we showed that ALE can be applied in pathogens of interest to study antibiotic resistance evolution and prediction of clinical resistance mechanisms, as supported by the significant overlap of mutations identified via ALE and those reported in clinical isolates.

A novel evolution tree for analyzing the global energy consumption structure

Systematically organizing and analyzing the energy consumption structure of the world can reveal the organic connections between countries. Furthermore, such tasks can provide a global reference system for each country, enabling each one to adjust and optimize its energy consumption structure. Most previous studies of the global energy consumption structure overlooked the associations between countries and the evolutionary trends associated with the energy consumption structures of countries. This paper analyzes the evolution of the global energy consumption structure using an evolution tree model. The visual structure of this model provides a novel perspective for understanding and analyzing the underlying trends. First, 144 countries and regions are categorized into four different types using the k-means clustering algorithm. Countries and regions that belong to the same type generally follow similar evolutionary paths. Moreover, type IV countries, which are mainly developed countries, have the most diverse energy consumption structures. By contrast, the energy consumption structures of other types of countries and regions can be improved. Countries can be located in the global energy consumption structure of the evolution tree, and these locations can provide a basis for improving the energy consumption structure of a country based on similar countries that are more diverse.

Magma storage and evolution of the most recent effusive and explosive eruptions from Yellowstone Caldera

Between 70 and 175 ka, over 350 km3 of high-silica rhyolite magma erupted both effusively and explosively from within the Yellowstone Caldera. Phenocrysts in all studied lavas and tuffs are remarkably homogenous at the crystal, eruption, and caldera-scale, and yield QUILF temperatures of 750 ± 25 °C. Phase equilibrium experiments replicate the observed phenocryst assemblage at those temperatures and suggest that the magmas were all stored in the upper crust. Quartz-hosted glass inclusions contain 1.0–2.5 % H2O and 50–600 ppm CO2, but some units are relatively rich in CO2 (300–600 ppm) and some are CO2-poor (50–200 ppm). The CO2-rich magmas were stored at 90–150 MPa and contained a fluid that was 60–75 mol% CO2. CO2-poor magmas were stored at 50–70 MPa, with a more H2O-rich fluid ( $$X_{{{\text{CO}}_{2} }}$$ = 40–60 %). Storage pressures and volatiles do not correlate with eruption age, volume, or style. Trace-element contents in glass inclusions and host matrix glass preserve a systematic evolution produced by crystal fractionation, estimated to range from 36 ± 12 to 52 ± 12 wt%. Because the erupted products contain <10 wt% crystals, crystal-poor melts likely separated from evolving crystal-rich mushes prior to eruption. In the Tuffs of Bluff Point and Cold Mountain Creek, matrix glass is less evolved than most inclusions, which may indicate that more primitive rhyolite was injected into the reservoir just before those eruptions. The presence and dissolution of granophyre in one flow may record evidence for heating prior to eruption and also demonstrate that the Yellowstone magmatic system may undergo rapid changes. The variations in depth suggest the magmas were sourced from multiple chambers that follow similar evolutionary paths in the upper crust.

147Sm‐143Nd and 176Lu‐176Hf systematics of eucrite and angrite meteorites

AbstractComparative planetary geochemistry provides insight into the origin and evolutionary paths of planetary bodies in the inner solar system. The eucrite and angrite achondrite groups are particularly interesting because they show evidence of early planetary differentiation. We present 147Sm‐143Nd and 176Lu‐176Hf analyses of eight noncumulate (basaltic) eucrites, two cumulate eucrites, and three angrites, which together place new constraints on the evolution and differentiation histories of the crusts of the eucrite and angrite parent bodies and their mantle mineralogies. The chemical compositions of both eucrites and angrites indicate similar evolutionary paths and petrogenetic models with formation and isolation of differentiated crustal reservoirs associated with segregation of ilmenite. We report a 147Sm‐143Nd mineral isochron age for the Moama cumulate eucrite of 4519 ± 34 Ma (MSWD = 1.3). This age indicates protracted magmatism within deep crustal layers of the eucrite parent body lasting up to about 50 Ma after the formation of the solar system. We further demonstrate that the isotopic compositions of constituent minerals are compromised by secondary processes hindering precise determination of mineral isochron ages of basaltic eucrites and angrites. We interpret the changes in geochemistry and, consequently, the erroneous 147Sm‐143Nd and 176Lu‐176Hf internal mineral isochron ages of basaltic eucrites and angrites as the result of metamorphic events such as impacts (effects from pressure, temperature, and peak shock duration) on the surfaces of the eucrite and angrite parent bodies.

Accretion disc particle accretion in major merger simulations

A recent approach to simulating localized feedback from active galactic nuclei by Power et al. (2011) uses an accretion disc particle to represent both the black hole and its accretion disc. We have extrapolated and adapted this approach to simulations of Milky Way-sized galaxy mergers containing black holes and explored the impact of the various parameters in this model as well as its resolution dependence. The two key parameters in the model are an effective accretion radius, which determines the radius within which gas particles are added to the accretion disc, and a viscous time-scale which determines how long it takes for material in the accretion disc to accrete on to the black hole itself. We find that there is a limited range of permitted accretion radii and viscous time-scales, with unphysical results produced outside this range. For permitted model parameters, the nuclear regions of simulations with the same resolution follow similar evolutionary paths, producing final black hole masses that are consistent within a factor of two. When comparing the resolution dependence of the model, there is a trend towards higher resolution producing slightly lower mass black holes, but values for the two resolutions studied again agree within a factor of two. We also compare these results to two other AGN feedback algorithms found in the literature. While the evolution of the systems vary, most notably the intermediate total black hole mass, the final black hole masses differ by less than a factor of five amongst all of our models, and the remnants exhibit similar structural parameters. The implication of this accretion model is that, unlike most accretion algorithms, a decoupling of the accretion rate on to the black hole and the local gas properties is permitted and obtained; this allows for black hole growth even after feedback has prevented additional accretion events on to the disc.

Genome characterisation of the genus Francisella reveals insight into similar evolutionary paths in pathogens of mammals and fish.

BackgroundPrior to this study, relatively few strains of Francisella had been genome-sequenced. Previously published Francisella genome sequences were largely restricted to the zoonotic agent F. tularensis. Only limited data were available for other members of the Francisella genus, including F. philomiragia, an opportunistic pathogen of humans, F. noatunensis, a serious pathogen of farmed fish, and other less well described endosymbiotic species.ResultsWe determined the phylogenetic relationships of all known Francisella species, including some for which the phylogenetic positions were previously uncertain. The genus Francisella could be divided into two main genetic clades: one included F. tularensis, F. novicida, F. hispaniensis and Wolbachia persica, and another included F. philomiragia and F. noatunensis.Some Francisella species were found to have significant recombination frequencies. However, the fish pathogen F. noatunensis subsp. noatunensis was an exception due to it exhibiting a highly clonal population structure similar to the human pathogen F. tularensis.ConclusionsThe genus Francisella can be divided into two main genetic clades occupying both terrestrial and marine habitats. However, our analyses suggest that the ancestral Francisella species originated in a marine habitat. The observed genome to genome variation in gene content and IS elements of different species supports the view that similar evolutionary paths of host adaptation developed independently in F. tularensis (infecting mammals) and F. noatunensis subsp. noatunensis (infecting fish).

Origin of the Sox multienzyme complex system in ancient thermophilic bacteria and coevolution of its constituent proteins

The multienzyme complex SoxXABYZ(CD) 2, characteristic of facultatively chemolithotrophic Alphaproteobacteria, oxidizes both sulfone and sulfane sulfur species directly to sulfate, while a truncated SoxXABYZ oxidizes only sulfone sulfur in species of Chromatiaceae and Chlorobi. Here we phylogenetically analyzed SoxXA, SoxYZ and SoxCD sequences, correlated the results with earlier SoxB-based data, and postulated that the system originated in putatively common ancestors of Aquificae and Epsilonproteobacteria, and evolved through extensive horizontal gene transfer, accompanied by gain and/or loss of constituents by different lineages. However, in several Sox systems, particularly those from Alphaproteobacteria (and also Chromatiaceae and Chlorobi), there has been no extra gain or loss of constituents and all their proteins have similar evolutionary paths. This implies that the components of these systems have coevolved parallel to each other without any shuffling with other divergent systems. This, however, holds good only for those Sox systems, which render sulfur oxidation functions equivalent to the typical alphaproteobacterial process. We postulate that coevolution of all the proteins is essential for the typical modular function of Sox. Conversely, mosaic Sox systems (where constituents have disparate phylogenetic paths) are either nonfunctional or with activities deviated from typical systems. Monomeric Sox subunits of the mosaic systems, however, possess almost all the motifs and conserved domains critical for their designated activity and heterodimer formation. So what could be the basis of the functional discrepancies of the mosaic Sox systems? It appears that their discretely evolved heterodimers cannot interact among themselves in the same way as ideally envisaged in the modular Sox system, which in turn, may in some cases lead to novel adventitious reactions.

Distribution of megaplasmids in Lactobacillus salivarius and other lactobacilli.

The genome of Lactobacillus salivarius UCC118 includes a 242-kb megaplasmid, pMP118. We now show that 33 strains of L. salivarius isolated from humans and animals all harbor a megaplasmid, which hybridized with the repA and repE replication origin probes of pMP118. Linear megaplasmids that did not hybridize with the pMP118 repA probe were also found in some strains of L. salivarius, showing for the first time that a lactic acid bacterium has multiple megaplasmids. Phylogenetic analysis of the repE and groEL sequences of 28 L. salivarius strains suggested similar evolutionary paths for the chromosome and megaplasmid. Although the replication origin of circular megaplasmids in L. salivarius was highly conserved, genotypic and phenotypic comparisons revealed significant variation between megaplasmid-encoded traits. Furthermore, megaplasmids of sizes ranging from 120 kb to 490 kb were present in seven strains belonging to six other Lactobacillus species from among 91 strains and 47 species tested. The discovery of the widespread presence of megaplasmids in L. salivarius, and restricted carriage by other Lactobacillus species, provides an opportunity to study the contribution of large extrachromosomal replicons to the biology of Lactobacillus.

A Kinematically Selected, Metal‐poor Stellar Halo in the Outskirts of M31

We present evidence for a metal-poor, [Fe/H] ~- 1:4,σ = 0.2 dex, stellar halo component detectable at radii from 10 to 70 kpc, in our nearest giant spiral neighbor, the Andromeda galaxy. This metal-poor sample underlies the recently discovered extended rotating component and has no detected metallicity gradient. This discovery uses a large sample of 9861 radial velocities of red giant branch (RGB) stars obtained with the Keck II Telescope and DEIMOS spectrograph, with 827 stars with robust radial velocity measurements isolated kinematically to lie in the halo component primarily by windowing out the extended rotating component, which dominates the photometric profile of Andromeda out to<50 kpc (deprojected). The stars lie in 54 spectroscopic fields spread over an 8 deg^2 region, and are expected to fairly sample the halo to a radius of 70 kpc. The halo sample shows no significant evidence for rotation. Fitting a simple model in which the velocity dispersion of the component decreases with radius, we find a central velocity dispersion of 152 km s^(-1) decreasing by 0.90 km s^(-1) kpc^(-1). By fitting a cosmologically motivated NFW halo model to the halo stars we constrain the virial mass of M31 to be greater than 9.0 x 10^(11) M_☉ with 99% confidence. The properties of this halo component are very similar to that found in our Milky Way, revealing that these roughly equal mass galaxies may have led similar accretion and evolutionary paths in the early universe.

Whole-Genome Sequence ofListeria welshimeriReveals Common Steps in Genome Reduction withListeria innocuaas Compared toListeria monocytogenes

We present the complete genome sequence of Listeria welshimeri, a nonpathogenic member of the genus Listeria. Listeria welshimeri harbors a circular chromosome of 2,814,130 bp with 2,780 open reading frames. Comparative genomic analysis of chromosomal regions between L. welshimeri, Listeria innocua, and Listeria monocytogenes shows strong overall conservation of synteny, with the exception of the translocation of an F(o)F(1) ATP synthase. The smaller size of the L. welshimeri genome is the result of deletions in all of the genes involved in virulence and of "fitness" genes required for intracellular survival, transcription factors, and LPXTG- and LRR-containing proteins as well as 55 genes involved in carbohydrate transport and metabolism. In total, 482 genes are absent from L. welshimeri relative to L. monocytogenes. Of these, 249 deletions are commonly absent in both L. welshimeri and L. innocua, suggesting similar genome evolutionary paths from an ancestor. We also identified 311 genes specific to L. welshimeri that are absent in the other two species, indicating gene expansion in L. welshimeri, including horizontal gene transfer. The species L. welshimeri appears to have been derived from early evolutionary events and an ancestor more compact than L. monocytogenes that led to the emergence of nonpathogenic Listeria spp.

Monkey see, monkey do

A new study shows that the independent adaptation to a ruminant lifestyle in two leaf-eating monkeys relied on parallel amino acid substitutions in ribonuclease gene duplicates. This discovery suggests that, given similar initial conditions, proteins may repeatedly follow similar adaptive evolutionary paths.

Leonardo da Vinci’s Sforza Monument Horse: The Art and the Engineering ed. by Diane Cole Ahl

1020 Book Reviews TECHNOLOGY AND CULTURE had not originally foreseen or intended. Importantly, Bugos exam­ ines these practices and procedures within the context of the larger social, political, and economic forces shaping the various constituen­ cies into the engineering teams that, in turn, shaped the parts of the F-4. Historians of business, technology, and the military will find Engi­ neering the F-4 richly rewarding, as will sociologists and members of the military profession. More than thirty years after it first flew, the airframe we know as the F-4 still constituted an important part of America’s airpower system, but in ways its originators never intended during its youth. The F-4’s role in the starting lineup of the Gulf War had evolved from its roles in interception, air superiority, and ground attack to firing HARM missiles and photographing tanks on the desert. McDonnell’s F-15 and General Dynamic’s F-16 have fol­ lowed similar evolutionary paths. With the air force looking forward to fielding the Lockheed-Martin F-22, we can, as Bugos suggests, count on it to assume future roles its originators never intended as the engineering managers who are progressively responsible for the system and the post-cold war military-industrial complex shape its future. RoyF. Houchin II Major Houchin is professor of military history at the School of Advanced Airpower Studies, Maxwell AJFB, Montgomery, Alabama. He is working on a manuscript for the Smithsonian Institution Press, tentatively titled The Legacy ofDyna-Soar: The History ofAir Force Hypersonic R&D, 1944-1963. Leonardo da Vinci’s Sforza Monument Horse: The Art and the Engineering. Edited by Diane Cole Ahi. Bethlehem, Penn.: Lehigh University Press, 1995. Pp. 152; illustrations, tables, notes, index. $55.00 (cloth). Any catalog of magnificent but never-constructed monuments would surely include Leonardo da Vinci’s colossal equestrian statue of Francesco Sforza. Commissioned in the 1480s by Ludovico Sforza of Milan to honor his father, it was planned as “the largest eques­ trian monument ever known” (p. 21). By 1493 Leonardo had fabri­ cated a clay model ready for casting. To complete the project, a large pit had to be constructed as well as a complex system of multiple furnaces for melting the bronze. Leonardo progressed to the point of constructing a mold in sections from the clay model, and he had amassed the requisite bronze. Fate intervened, however, in the form of the French invasion of Italy. As a precautionary measure, Ludov­ ico sent the bronze intended for the horse to Ferrara to be made into cannon. French troops destroyed the clay model in “target prac­ tice” in 1499, and the molds were subsequently lost. What remain are Leonardo’s notes, including important sheets from Madrid Codex technology and culture Book Reviews 1021 II, beautiful drawings of horses, and intriguing illustrations of equip­ ment. The papers in this collection were originally presented at a sympo­ sium on the Sforza monument held in April 1991 at Lafayette Col­ lege and Lehigh University in Pennsylvania. The gathering was in­ spired and in part supported by the late Charles C. Dent, airline pilot, art collector, and, in the last fifteen years of his life, avid propo­ nent ofa project to construct Leonardo’s equestrian monument and place it in the courtyard of the Sforza Castle in Milan. The volume includes essays by art historians, casting experts, and cultural histori­ ans, among others. It provides an excellent introduction to Leon­ ardo’s planned monument as well as to equestrian statuary, Renais­ sance bronze casting, the cultural place of the horse in 15th-century Italy, and modern replication efforts. Carlo Pedretti discusses in detail the known documentation of the Sforza monument, including the relevant drawings. He elucidates the local context by describing the actual locations in Milan where Leonardo worked on the horse, and he lays out the evidence for the dates of various phases of the project. Pedretti’s essay brings home the fact that there are numerous unknowns about the Sforza horse, including what it was finally going to look like. From a different per­ spective, Martin Kemp investigates the relevant drawings and studies of horses by Leonardo. He suggests that Leonardo’s...

SPH simulations of tidally unstable accretion discs in cataclysmic variables

We numerically study the precessing disk model for superhump in the SU~UMa subclass of cataclysmic variables, using a two dimensional SPH code specifically designed for thin disk problems. Two disk simulations for a binary with mass ratio $q=\frac{3}{17}$ (similar to OY~Car) are performed, in order to investigate the Lubow (1991 a,b) tidal resonance instability mechanism. In the first calculation, a disk evolves under steady mass transfer from $L_1$. In the second simulation, mass is added in Keplerian orbit to the inner disk. The two disks follow similar evolutionary paths. However the $L_1$ stream-disk interaction is found to slow the disk's radial expansion and to circularise gas orbits. The initial eccentricity growth in our simulations is exponential at a rate slightly less than predicted by Lubow (1991a). We do not observe a clearing of material from the resonance region via the disk's tidal response to the $m=2$ component of the binary potential as was described in Lubow (1992). Instead the $m=2$ response weakens as the disk eccentricty increases. Both disks reach an eccentric equilibrium state, in which they undergo prograde precession. The rate of viscous energy dissipation in the disks has a periodic excess with a period matching the disk's rotation. The source is identified as a large region in the outer disk, and the mechanism by which it is produced is identified. The time taken for the periodic excess to develop is consistent with the first appearance of superhumps in a superoutburst.