Deep MOS Spectroscopy of NGC 1316 Globular Clusters

The giant elliptical galaxy NGC 1316 is the brightest galaxy in the Fornax cluster, and displays a number of morphological features that might be interpreted as an intermediate age merger remanent ($\sim$3 Gyr). Based on the idea that globular clusters systems (GCS) constitute genuine tracers of the formation and evolution of their host galaxies, we conducted a spectroscopic study of approximately 40 globular clusters (GCs) candidates associated with this interesting galaxy. We determined ages, metallicities, and $\alpha$-element abundances for each GC present in the sample, through the measurement of different Lick indices and their subsequent comparison with simple stellar populations models (SSPs).Comment: 5 pages, 3 figure

Solenodon genome reveals convergent evolution of venom in eulipotyphlan mammals

Venom systems are key adaptations that have evolved throughout the tree of life and typically facilitate predation or defense. Despite venoms being model systems for studying a variety of evolutionary and physiological processes, many taxonomic groups remain understudied, including venomous mammals. Within the order Eulipotyphla, multiple shrew species and solenodons have oral venom systems. Despite morphological variation of their delivery systems, it remains unclear whether venom represents the ancestral state in this group or is the result of multiple independent origins. We investigated the origin and evolution of venom in eulipotyphlans by characterizing the venom system of the endangered Hispaniolan solenodon (Solenodon paradoxus). We constructed a genome to underpin proteomic identifications of solenodon venom toxins, before undertaking evolutionary analyses of those constituents, and functional assessments of the secreted venom. Our findings show that solenodon venom consists of multiple paralogous kallikrein 1 (KLK1) serine proteases, which cause hypotensive effects in vivo, and seem likely to have evolved to facilitate vertebrate prey capture. Comparative analyses provide convincing evidence that the oral venom systems of solenodons and shrews have evolved convergently, with the 4 independent origins of venom in eulipotyphlans outnumbering all other venom origins in mammals. We find that KLK1s have been independently coopted into the venom of shrews and solenodons following their divergence during the late Cretaceous, suggesting that evolutionary constraints may be acting on these genes. Consequently, our findings represent a striking example of convergent molecular evolution and demonstrate that distinct structural backgrounds can yield equivalent functions

Solenodon genome reveals convergent evolution of venom in eulipotyphlan mammals

Venom systems are key adaptations that have evolved throughout the tree of life and typically facilitate predation or defense. Despite venoms being model systems for studying a variety of evolutionary and physiological processes, many taxonomic groups remain understudied, including venomous mammals. Within the order Eulipotyphla, multiple shrew species and solenodons have oral venom systems. Despite morphological variation of their delivery systems, it remains unclear whether venom represents the ancestral state in this group or is the result of multiple independent origins. We investigated the origin and evolution of venom in eulipotyphlans by characterizing the venom system of the endangered Hispaniolan solenodon (Solenodon paradoxus). We constructed a genome to underpin proteomic identifications of solenodon venom toxins, before undertaking evolutionary analyses of those constituents, and functional assessments of the secreted venom. Our findings show that solenodon venom consists of multiple paralogous kallikrein 1 (KLK1) serine proteases, which cause hypotensive effects in vivo, and seem likely to have evolved to facilitate vertebrate prey capture. Comparative analyses provide convincing evidence that the oral venom systems of solenodons and shrews have evolved convergently, with the 4 independent origins of venom in eulipotyphlans outnumbering all other venom origins in mammals. We find that KLK1s have been independently coopted into the venom of shrews and solenodons following their divergence during the late Cretaceous, suggesting that evolutionary constraints may be acting on these genes. Consequently, our findings represent a striking example of convergent molecular evolution and demonstrate that distinct structural backgrounds can yield equivalent functions

Merging paleobiology with conservation biology to guide the future of terrestrial ecosystems

Conservation of species and ecosystems is increasingly difficult because anthropogenic impacts are pervasive and accelerating. Under this rapid global change, maximizing conservation success requires a paradigm shift from maintaining ecosystems in idealized past states toward facilitating their adaptive and functional capacities, even as species ebb and flow individually. Developing effective strategies under this new paradigm will require deeper understanding of the long-term dynamics that govern ecosystem persistence and reconciliation of conflicts among approaches to conserving historical versus novel ecosystems. Integrating emerging information from conservation biology, paleobiology, and the Earth sciences is an important step forward on the path to success. Maintaining nature in all its aspects will also entail immediately addressing the overarching threats of growing human population, overconsumption, pollution, and climate change.Peer reviewe

Genetics Reveal the Origin and Timing of a Cryptic Insular Introduction of Muskrats in North America

<div><p>The muskrat, <i>Ondatra zibethicus</i>, is a semiaquatic rodent native to North America that has become a highly successful invader across Europe, Asia, and South America. It can inflict ecological and economic damage on wetland systems outside of its native range. Anecdotal evidence suggests that, in the early 1900s, a population of muskrats was introduced to the Isles of Shoals archipelago, located within the Gulf of Maine, for the purposes of fur harvest. However, because muskrats are native to the northeastern coast of North America, their presence on the Isles of Shoals could be interpreted as part of the native range of the species, potentially obscuring management planning and biogeographic inferences. To investigate their introduced status and identify a historic source population, muskrats from Appledore Island of the Isles of Shoals, and from the adjacent mainland of Maine and New Hampshire, were compared for mitochondrial cytochrome <i>b</i> sequences and allele frequencies at eight microsatellite loci. Appledore Island muskrats consistently exhibited reduced genetic diversity compared with mainland populations, and displayed signatures of a historic bottleneck. The distribution of mitochondrial haplotypes is suggestive of a New Hampshire source population. The data presented here are consistent with a human-mediated introduction that took place in the early 1900s. This scenario is further supported by the zooarchaeological record and island biogeographic patterns. This is the first genetic study of an introduced muskrat population within US borders and of any island muskrat population, and provides an important contrast with other studies of introduced muskrat populations worldwide.</p></div

Summary of parameters used in <i>M</i>-ratio analyses used to detect significant reductions in population size.

<p>M_avg is average simulated <i>M</i>-ratio value for a given set of parameters and empirical microsatellite data; M_c is the critical value. M_avg and M_c were generated for Δ_g values of 2.8 and 3.5.</p><p>* indicates N_e values within the range calculated with long-term estimators.</p>a<p> = <b>Δ_g</b> value of 2.8;</p>b<p> = <b>Δ_g</b> value of 3.5.</p><p>Summary of parameters used in <i>M</i>-ratio analyses used to detect significant reductions in population size.</p

Map of study region depicting Appledore Island within the Isles of Shoals and in relation to the northeastern US coastline.

<p>Dashed gray lines represent state boundaries. Circles represent generalized population sampling locations on the mainland, with larger circles indicative of 4+ samples, and smaller circles of one. Appledore Island is highlighted in green (see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0111856#pone.0111856.s001" target="_blank">Figure S1</a> for fine-scale Appledore Island sampling).</p

F_ST values calculated for microsatellite DNA at seven loci, <i>P</i><0.0001 for all pairwise comparisons.

<p>Mainland is ME and NH combined as a single population.</p><p>F_ST values calculated for microsatellite DNA at seven loci, <i>P</i><0.0001 for all pairwise comparisons.</p

Mismatch distribution for A. the mainland population, ME and NH pooled, and B. AP only.

<p>Frequency is represented on the vertical axis. Solid gray lines indicate expected values and blue circles represent observed values. The expected frequency is based on a constant population size and demographic equilibrium. Raggedness statistics, <i>r</i> = 0.0592 and 0.6729 for <b>A</b>. and <b>B</b>., respectively.</p

TCS haplotype network for mitochondrial cytochrome <i>b</i> haplotypes.

<p>Size of circles is proportional to the number of individuals with that haplotype, where the largest circle depicts 25+ individuals and the smallest depicts one individual. Letters correspond to haplotypes described in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0111856#pone-0111856-t001" target="_blank">Table 1</a>. Each node represents a 1-bp change in nucleotide sequence, and hashes along a node represent probable missing haplotypes. Light blue shows AP, dark blue shows NH, and dark pink shows ME. Note that haplotype J is only found in AP and the coastal port of Portsmouth, NH.</p