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Full-Text Articles in Ecology and Evolutionary Biology

African Land Mammal Ages, John Van Couvering, Eric Delson Dec 2020

African Land Mammal Ages, John Van Couvering, Eric Delson

Publications and Research

We define 17 African land mammal ages, or AFLMAs, covering the Cenozoic record of the Afro-arabian continent, the planet’s second largest land mass. While fossiliferous deposits are absent on the eroded plateau of the continent’s interior, almost 800 fossil genera from over 350 locations have now been identified in coastal deposits, karst caves, and in the Neogene rift valleys. Given a well-developed geochronologic framework, together with continuing revision to the fossil record—both stimulated by the story of human evolution in Africa—and also to compensate for the variation in fossil ecosystems across such great distances, the AFLMAs are biochronological units defined …


A Putative Chordate Luciferase From A Cosmopolitan Tunicate Indicates Convergent Bioluminescence Evolution Across Phyla, Michael Tessler, Jean P. Gaffney, Anderson G. Oliveira, Andrew Guarnaccia, Krista C. Dobi, Nehaben A. Gujarati, Moira Galbraith, Jeremy D. Mirza, John S. Sparks, Vincent A. Pieribone, Robert J. Wood, David F. Gruber Oct 2020

A Putative Chordate Luciferase From A Cosmopolitan Tunicate Indicates Convergent Bioluminescence Evolution Across Phyla, Michael Tessler, Jean P. Gaffney, Anderson G. Oliveira, Andrew Guarnaccia, Krista C. Dobi, Nehaben A. Gujarati, Moira Galbraith, Jeremy D. Mirza, John S. Sparks, Vincent A. Pieribone, Robert J. Wood, David F. Gruber

Publications and Research

Pyrosomes are tunicates in the phylum Chordata, which also contains vertebrates. Their gigantic blooms play important ecological and biogeochemical roles in oceans. Pyrosoma, meaning “firebody”, derives from their brilliant bioluminescence. The biochemistry of this light production is unknown, but has been hypothesized to be bacterial in origin. We found that mixing coelenterazine—a eukaryote-specific luciferin—with Pyrosoma atlanticum homogenate produced light. To identify the bioluminescent machinery, we sequenced P. atlanticum transcriptomes and found a sequence match to a cnidarian luciferase (RLuc). We expressed this novel luciferase (PyroLuc) and, combined with coelenterazine, it produced light. A similar gene was recently predicted from a …


Genomic Adaptations To Salinity Resist Gene Flow In The Evolution Of Floridian Watersnakes, Rhett M. Rautsaw, Tristan D. Schramer, Rachel Acuña, Lindsay N. Arick, Mark Dimeo, Kathryn P. Mercier, Michael Schrum, Andrew J. Mason, Mark J. Margres, Jason L. Strickland, Christopher L. Parkinson Oct 2020

Genomic Adaptations To Salinity Resist Gene Flow In The Evolution Of Floridian Watersnakes, Rhett M. Rautsaw, Tristan D. Schramer, Rachel Acuña, Lindsay N. Arick, Mark Dimeo, Kathryn P. Mercier, Michael Schrum, Andrew J. Mason, Mark J. Margres, Jason L. Strickland, Christopher L. Parkinson

Publications and Research

The migration-selection balance often governs the evolution of lineages, and speciation with gene flow is now considered common across the tree of life. Ecological speciation is a process that can facilitate divergence despite gene flow due to strong selective pressures caused by ecological differences; however, the exact traits under selection are often unknown. The transition from freshwater to saltwater habitats provides strong selection targeting traits with osmoregulatory function. Several lineages of North American watersnakes (Nerodia spp.) are known to occur in saltwater habitat and represent a useful system for studying speciation by providing an opportunity to investigate gene flow …


Not Withering On The Evolutionary Vine: Systematic Revision Of The Brown Vine Snake (Reptilia: Squamata: Oxybelis) From Its Northern Distribution, Robert C. Jadin, Christopher Blair, Sarah A. Orlofske, Michael J. Jowers, Gilson A. Rivas, Laurie J. Vitt, Julie M. Ray, Eric N. Smith, John C. Murphy Oct 2020

Not Withering On The Evolutionary Vine: Systematic Revision Of The Brown Vine Snake (Reptilia: Squamata: Oxybelis) From Its Northern Distribution, Robert C. Jadin, Christopher Blair, Sarah A. Orlofske, Michael J. Jowers, Gilson A. Rivas, Laurie J. Vitt, Julie M. Ray, Eric N. Smith, John C. Murphy

Publications and Research

The genus Oxybelis currently is composed of four taxa despite numerous studies suggesting and describing multiple taxa within the O. aeneus complex. Here, we utilize a multilocus molecular dataset (i.e. cyt b, ND4, 12S, 16S, cmos, PRLR, 3663 bp) to conduct phylogenetic analyses to assess the evolutionary history of Oxybelis. Our molecular analyses find three major lineages of Oxybelis (i.e. O. aeneus complex, O. brevirostris, O. fulgidus complex) with a sister relationship between O. brevirostris and the O. aeneus complex to the exclusion of the O. fulgidus complex. More specifically, O. aeneus appears to harbor at least …


Spatiotemporal Genetic Diversity Of Lions Reveals The Influence Of Habitat Fragmentation Across Africa, Caitlin J. Curry, Brian W. Davis, Laura D. Bertola, Paula A. White, William J. Murphy, James N. Derr Jul 2020

Spatiotemporal Genetic Diversity Of Lions Reveals The Influence Of Habitat Fragmentation Across Africa, Caitlin J. Curry, Brian W. Davis, Laura D. Bertola, Paula A. White, William J. Murphy, James N. Derr

Publications and Research

Direct comparisons between historical and contemporary populations allow for detecting changes in genetic diversity through time and assessment of the impact of habitat fragmentation. Here, we determined the genetic architecture of both historical and modern lions to document changes in genetic diversity over the last century. We surveyed microsatellite and mitochondrial genome variation from 143 high-quality museum specimens of known provenance, allowing us to directly compare this information with data from several recently published nuclear and mitochondrial studies. Our results provide evidence for male-mediated gene flow and recent isolation of local subpopulations, likely due to habitat fragmentation. Nuclear markers showed …


Metabolomic Differences Between Invasive Alien Plants From Native And Invaded Habitats, Sarah A. Skubel, Xiaoyang Su, Alexander Poulev, Llewellyn C. Foxcroft, Vyacheslav Dushenkov, Ilya Raskin Jun 2020

Metabolomic Differences Between Invasive Alien Plants From Native And Invaded Habitats, Sarah A. Skubel, Xiaoyang Su, Alexander Poulev, Llewellyn C. Foxcroft, Vyacheslav Dushenkov, Ilya Raskin

Publications and Research

Globalization facilitated the spread of invasive alien species (IAS), undermining the stability of the world’s ecosystems. We investigated the metabolomic profiles of three IAS species: Chromolaena odorata (Asteraceae) Datura stramonium (Solanaceae), and Xanthium strumarium (Asteraceae), comparing metabolites of individual plants in their native habitats (USA), to their invasive counterparts growing in and around Kruger National Park (South Africa, ZA). Metabolomic samples were collected using RApid Metabolome Extraction and Storage (RAMES) technology, which immobilizes phytochemicals on glass fiber disks, reducing compound degradation, allowing long-term, storage and simplifying biochemical analysis. Metabolomic differences were analyzed using ultra-performance liquid chromatography-mass spectrometry (UPLC-MS) of samples …


Snapshots Of Human Anatomy, Locomotion, And Behavior From Late Pleistocene Footprints At Engare Sero, Tanzania, Kevin Hatala, William E. H. Harcourt-Smith, Adam D. Gordon, Brian W. Zimmer, Brian G. Richmond, Briana L. Pobiner, David J. Green, Adam Metallo, Vince Rossi, Cynthia M. Liutkus-Pierce May 2020

Snapshots Of Human Anatomy, Locomotion, And Behavior From Late Pleistocene Footprints At Engare Sero, Tanzania, Kevin Hatala, William E. H. Harcourt-Smith, Adam D. Gordon, Brian W. Zimmer, Brian G. Richmond, Briana L. Pobiner, David J. Green, Adam Metallo, Vince Rossi, Cynthia M. Liutkus-Pierce

Publications and Research

Fossil hominin footprints preserve data on a remarkably short time scale compared to most other fossil evidence, offering snapshots of organisms in their immediate ecological and behavioral contexts. Here, we report on our excavations and analyses of more than 400 Late Pleistocene human footprints from Engare Sero, Tanzania. The site represents the largest assemblage of footprints currently known from the human fossil record in Africa. Speed estimates show that the trackways reflect both walking and running behaviors. Estimates of group composition suggest that these footprints were made by a mixed-sex and mixed-age group, but one that consisted of mostly adult …


Investigation Of An Elevational Gradient Reveals Strong Differences Between Bacterial And Eukaryotic Communities Coinhabiting Nepenthes Phytotelmata, Kadeem J. Gilbert, Leonora S. Bittleston, Mark Arcebal K. Naive, Anthony E. Kiszewski, Perry Archival C. Buenavente, David J. Lohman, Naomi E. Pierce Apr 2020

Investigation Of An Elevational Gradient Reveals Strong Differences Between Bacterial And Eukaryotic Communities Coinhabiting Nepenthes Phytotelmata, Kadeem J. Gilbert, Leonora S. Bittleston, Mark Arcebal K. Naive, Anthony E. Kiszewski, Perry Archival C. Buenavente, David J. Lohman, Naomi E. Pierce

Publications and Research

Elevation is an important determinant of ecological community composition. It integrates several abiotic features and leads to strong, repeatable patterns of community structure, including changes in the abundance and richness of numerous taxa. However, the influence of elevational gradients on microbes is understudied relative to plants and animals. To compare the influence of elevation on multiple taxa simultaneously, we sampled phytotelm communities within a tropical pitcher plant (Nepenthes mindanaoensis) along a gradient from 400 to 1200 m a.s.l. We use a combination of metabarcoding and physical counts to assess diversity and richness of bacteria, micro-eukaryotes, and arthropods, and compare the …


Variation In Brown Rat Cranial Shape Shows Directional Selection Over 120 Years In New York City, Emily E. Puckett, Emma Sherratt, Matthew Combs, Elizabeth J. Carlen, William Harcourt-Smith, Jason Munshi-South Mar 2020

Variation In Brown Rat Cranial Shape Shows Directional Selection Over 120 Years In New York City, Emily E. Puckett, Emma Sherratt, Matthew Combs, Elizabeth J. Carlen, William Harcourt-Smith, Jason Munshi-South

Publications and Research

Urbanization exposes species to novel environments and selection pressures that may change morphological traits within a population. We investigated how the shape and size of crania and mandibles changed over time within a population of brown rats (Rattus norvegicus) living in Manhattan, New York, USA, a highly urbanized environment. We measured 3D landmarks on the cranium and mandible of 62 adult individuals sampled in the 1890s and 2010s. Static allometry explained approximately 22% of shape variation in crania and mandible datasets, while time accounted for approximately 14% of variation. We did not observe significant changes in skull size through time …


Network Structure Of Vertebrate Scavenger Assemblages At The Global Scale: Drivers And Ecosystem Functioning Implications, Esther Sebastián-González, Zebensui Morales-Reyes, Francisco Botella, Lara Naves-Alegre, Juan M. Pérez-García, Patricia Mateo-Tomás, Pedro P. Olea, Marcos Moleón, Jomar M. Barbosa, Fernando Hiraldo, Eneko Arrondo, José A. Donázar, Ainara Cortés-Avizanda, Nuria Selva, Sergio A. Lambertucci, Aishwarya Bhattacharjee, Alexis L. Brewer, Erin F. Abernethy, Kelsey L. Turner, James C. Beasley, Travis L. Devault, Hannah C. Gerke, Olin E. Rhodes Jr, Andrés Ordiz, Camilla Wikenros, Barbara Zimmermann, Petter Wabakken, Christopher C. Wilmers, Justine A. Smith, Corinne Kendall, Darcy Ogada, Ethan Frehner, Maximilian L. Allen, Heiko U. Wittmer, James R. A. Butler, Johan T. Du Toit, Antoni Margalida, Pilar Oliva-Vidal, David Wilson, Klemen Jerina, Miha Krofel, Rich Kostecke, Richard Inger, Esra Per, Yunus Ayhan, Hasan Ulusoy, Doğanay Vural, Akino Inagaki, Shinsuke Koike, Arockianathan Samson, Paula L. Perrig, Emma Spencer, Thomas M. Newsome, Marco Heurich, José D. Anadón, Evan R. Buechley, José A. Sánchez-Zapata Jan 2020

Network Structure Of Vertebrate Scavenger Assemblages At The Global Scale: Drivers And Ecosystem Functioning Implications, Esther Sebastián-González, Zebensui Morales-Reyes, Francisco Botella, Lara Naves-Alegre, Juan M. Pérez-García, Patricia Mateo-Tomás, Pedro P. Olea, Marcos Moleón, Jomar M. Barbosa, Fernando Hiraldo, Eneko Arrondo, José A. Donázar, Ainara Cortés-Avizanda, Nuria Selva, Sergio A. Lambertucci, Aishwarya Bhattacharjee, Alexis L. Brewer, Erin F. Abernethy, Kelsey L. Turner, James C. Beasley, Travis L. Devault, Hannah C. Gerke, Olin E. Rhodes Jr, Andrés Ordiz, Camilla Wikenros, Barbara Zimmermann, Petter Wabakken, Christopher C. Wilmers, Justine A. Smith, Corinne Kendall, Darcy Ogada, Ethan Frehner, Maximilian L. Allen, Heiko U. Wittmer, James R. A. Butler, Johan T. Du Toit, Antoni Margalida, Pilar Oliva-Vidal, David Wilson, Klemen Jerina, Miha Krofel, Rich Kostecke, Richard Inger, Esra Per, Yunus Ayhan, Hasan Ulusoy, Doğanay Vural, Akino Inagaki, Shinsuke Koike, Arockianathan Samson, Paula L. Perrig, Emma Spencer, Thomas M. Newsome, Marco Heurich, José D. Anadón, Evan R. Buechley, José A. Sánchez-Zapata

Publications and Research

The organization of ecological assemblages has important implications for ecosystem functioning, but little is known about how scavenger communities organize at the global scale. Here, we test four hypotheses on the factors affecting the network structure of terrestrial vertebrate scavenger assemblages and its implications on ecosystem functioning. We expect scavenger assemblages to be more nested (i.e. structured): 1) in species-rich and productive regions, as nestedness has been linked to high competition for carrion resources, and 2) regions with low human impact, because the most efficient carrion consumers that promote nestedness are large vertebrate scavengers, which are especially sensitive to human …


A Tale Of Winglets: Evolution Of Flight Morphology In Stick Insects, Yu Zeng, Connor O'Malley, Sonal Singhal, Faszly Rahim, Sehoon Park, Xin Chen, Robert Dudley Jan 2020

A Tale Of Winglets: Evolution Of Flight Morphology In Stick Insects, Yu Zeng, Connor O'Malley, Sonal Singhal, Faszly Rahim, Sehoon Park, Xin Chen, Robert Dudley

Publications and Research

The evolutionary transition between winglessness and a full-winged morphology requires selective advantage for intermediate forms. Conversely, repeated secondary wing reductions among the pterygotes indicates relaxation of such selection. However, evolutionary trajectories of such transitions are not well-characterized. The stick insects (Phasmatodea) exhibit diverse wing sizes at both interspecific and intersexual levels, and thus provide a system for examining how selection on flight capability, along with other selective forces, drives the evolution of flight-related morphology. Here, we examine variation in relevant morphology for stick insects using data from 1,100+ individuals representing 765 species. Although wing size varies along a continuous spectrum, …


Sperm Storage Reduces The Strength Of The Mate-Finding Allee Effect, María V. Jiménez-Franco, Andrés Giménez, Roberto C. Rodríguez-Caro, Ana Sanz-Aguilar, Francisco Botella, Jose D. Anadon, Thorsten Wiegand, Eva Graciá Jan 2020

Sperm Storage Reduces The Strength Of The Mate-Finding Allee Effect, María V. Jiménez-Franco, Andrés Giménez, Roberto C. Rodríguez-Caro, Ana Sanz-Aguilar, Francisco Botella, Jose D. Anadon, Thorsten Wiegand, Eva Graciá

Publications and Research

Mate searching is a key component of sexual reproduction that can have important implications for population viability, especially for the mate-finding Allee effect. Interannual sperm storage by females may be an adaptation that potentially attenuates mate limitation, but the demographic consequences of this functional trait have not been studied. Our goal is to assess the effect of female sperm storage durability on the strength of the mate-finding Allee effect and the viability of populations subject to low population density and habitat alteration. We used an individual-based simulation model that incorporates realistic representations of the demographic and spatial processes of our …


Scythes, Sickles And Other Blades: Defining The Diversity Of Pectoral Fin Morphotypes In Pachycormiformes, Jeff J. Liston, Anthony E. Maltese, Paul H. Lambers, Dominique Delsate, William E.H. Harcourt-Smith, Anneke H. Van Heteren Nov 2019

Scythes, Sickles And Other Blades: Defining The Diversity Of Pectoral Fin Morphotypes In Pachycormiformes, Jeff J. Liston, Anthony E. Maltese, Paul H. Lambers, Dominique Delsate, William E.H. Harcourt-Smith, Anneke H. Van Heteren

Publications and Research

The traditional terminology of ‘scythe’ or ‘sickle’ shaped is observed to be flawed as an effective descriptor for pectoral fin shape in pachycormids. The diversity of pachycormid pectoral fin shapes is assessed across the 14 recognised genera that preserve complete pectoral fins, and improved terms are defined to more effectively describe their form, supported by anatomical observation and aspect ratio analysis of individual fins, and corroborated by landmark analysis. Three clear and distinct pectoral fin structural morphotypes emerge (falceform, gladiform, falcataform), reflecting a diversity of pachycormid lifestyles throughout the Mesozoic, from agile pursuit predator to slow-cruising suspension feeder.


Rasp 4: Ancestral State Reconstruction Tool For Multiple Genes And Characters, Yan Yu, Christopher Blair, Xingjin He Oct 2019

Rasp 4: Ancestral State Reconstruction Tool For Multiple Genes And Characters, Yan Yu, Christopher Blair, Xingjin He

Publications and Research

With the continual progress of sequencing techniques, genome-scale data are increasingly used in phylogenetic studies. With more data from throughout the genome, the relationship between genes and different kinds of characters is receiving more attention. Here, we present version 4 of RASP, a software to reconstruct ancestral states through phylogenetic trees. RASP can apply generalized statistical ancestral reconstruction methods to phylogenies, explore the phylogenetic signal of characters to particular trees, calculate distances between trees, and cluster trees into groups. RASP 4 has an improved graphic user interface and is freely available from http://mnh.scu.edu.cn/soft/blog/RASP (program) and https://github.com/sculab/RASP (source code).


Venom Diversity And Evolution In The Most Divergent Cone Snail Genus Profundiconus, Guilia Fassio, Maria Vittoria Modica, Lou Mary, Paul Zaharias, Alexander E. Fedosov, Juliette Gorson, Yuri I. Kantor, Mandë E. Holford, Nicolas Puillandre Oct 2019

Venom Diversity And Evolution In The Most Divergent Cone Snail Genus Profundiconus, Guilia Fassio, Maria Vittoria Modica, Lou Mary, Paul Zaharias, Alexander E. Fedosov, Juliette Gorson, Yuri I. Kantor, Mandë E. Holford, Nicolas Puillandre

Publications and Research

Profundiconus is the most divergent cone snail genus and its unique phylogenetic position, sister to the rest of the family Conidae, makes it a key taxon for examining venom evolution and diversity. Venom gland and foot transcriptomes of Profundiconus cf. vaubani and Profundiconus neocaledonicus were de novo assembled, annotated, and analyzed for differential expression. One hundred and thirty-seven venom components were identified from P. cf. vaubani and 82 from P. neocaledonicus, with only four shared by both species. The majority of the transcript diversity was composed of putative peptides, including conotoxins, profunditoxins, turripeptides, insulin, and prohormone-4. However, there were also …


Spatial Upscaling Of Forest Response To Drought, Wei Fang, Peipei Xu, Tao Zhao, Xiang Zhao, Hui Luo, George Hendrey, Chuixiang Yi Oct 2019

Spatial Upscaling Of Forest Response To Drought, Wei Fang, Peipei Xu, Tao Zhao, Xiang Zhao, Hui Luo, George Hendrey, Chuixiang Yi

Publications and Research

We have integrated the observational capability of satellite remote sensing with plot-scale tree ring data to up-scale the evaluation of forest responses to drought. Satellite data, such as Normalized Difference Vegetation Index (NDVI), can provide a spatially continuous measure with limited temporal coverage, while tree Ring Width Index (RWI) provides accurate assessment with much longer time series local scales. Here, we explored the relationship between RWI and NDVI of three dominant species in the Southwestern United States (SWUS), and predicted RWI spatial distribution from 2001 to 2017 based on MODIS 1-km resolution NDVI data with stringent quality control. We detected …


Temporal Changes In Abundance–Occupancy Relationships Over 40 Years, Lisa L. Manne, Richard R. Veit Sep 2019

Temporal Changes In Abundance–Occupancy Relationships Over 40 Years, Lisa L. Manne, Richard R. Veit

Publications and Research

  1. Abundance–occupancy (A–O) relationships are widely documented for many organismal groups and regions, and have been used to gain an understanding of regional population and community trends. Monitoring changes in abundance and occupancy over time may be what is required to document changes in conservation status and needs for some species, communities, or areas.
  2. We hypothesize that if there is a higher proportion of declining species in one group of species compared with another (e.g., migratory species vs. permanent residents), then a consequence of that difference will be vastly different abundance–occupancy relationships. If this difference persists through time, then the resulting …


Multi-Scale Predictors Of Parasite Risk In Wild Male Savanna Baboons (Papio Cynocephalus), Bobby Habig, David A.W.A.M. Jansen, Mercy Y. Akinyi, Laurence R. Gesquiere, Susan C. Alberts, Elizabeth A. Archie Sep 2019

Multi-Scale Predictors Of Parasite Risk In Wild Male Savanna Baboons (Papio Cynocephalus), Bobby Habig, David A.W.A.M. Jansen, Mercy Y. Akinyi, Laurence R. Gesquiere, Susan C. Alberts, Elizabeth A. Archie

Publications and Research

Several factors are thought to shape male parasite risk in polygynous and polygynandrous mammals, including male-male competition, investment in potentially immunosuppressive hormones, and dispersal. Parasitism is also driven by processes occurring at larger scales, including host social groups and populations. To date, studies that test parasite-related costs of male behavior at all three scales—individual hosts, social groups, and the host population—remain rare. To fill this gap, we investigated multi-scale predictors of helminth parasitism in 97 male savanna baboons (Papio cynocephalus) living in the Amboseli ecosystem in Kenya over a 5-year span. Controlling for multi-scale processes, we found that many of …


Phylogenetic Trees And Networks Can Serve As Powerful And Complementary Approaches For Analysis Of Genomic Data, Christopher Blair, Cécile Ané Aug 2019

Phylogenetic Trees And Networks Can Serve As Powerful And Complementary Approaches For Analysis Of Genomic Data, Christopher Blair, Cécile Ané

Publications and Research

Genomic data have had a profound impact on nearly every biological discipline. In systematics and phylogenetics, the thousands of loci that are now being sequenced can be analyzed under the multispecies coalescent model (MSC) to explicitly account for gene tree discordance due to incomplete lineage sorting (ILS). However, the MSC assumes no gene flow post divergence, calling for additional methods that can accommodate this limitation. Explicit phylogenetic network methods have emerged, which can simultaneously account for ILS and gene flow by representing evolutionary history as a directed acyclic graph. In this point-of-view we highlight some of the strengths and limitations …


A Comparison Of Individual Learning And Social Learning In Zebrafish Through An Ethorobotics Approach, Yanpeng Yang, Romain J. G. Clément, Stefano Ghirlanda, Maurizio Porfiri Aug 2019

A Comparison Of Individual Learning And Social Learning In Zebrafish Through An Ethorobotics Approach, Yanpeng Yang, Romain J. G. Clément, Stefano Ghirlanda, Maurizio Porfiri

Publications and Research

Social learning is ubiquitous across the animal kingdom, where animals learn from group members about predators, foraging strategies, and so on. Despite its prevalence and adaptive benefits, our understanding of social learning is far from complete. Here, we study observational learning in zebrafish, a popular animal model in neuroscience. Toward fine control of experimental variables and high consistency across trials, we developed a novel robotics-based experimental test paradigm, in which a robotic replica demonstrated to live subjects the correct door to join a group of conspecifics. We performed two experimental conditions. In the individual training condition, subjects learned the correct …


Reduced Alphabet Of Prebiotic Amino Acids Optimally Encodes The Conformational Space Of Diverse Extant Protein Folds, Armando D. Solis Jul 2019

Reduced Alphabet Of Prebiotic Amino Acids Optimally Encodes The Conformational Space Of Diverse Extant Protein Folds, Armando D. Solis

Publications and Research

Background

There is wide agreement that only a subset of the twenty standard amino acids existed prebiotically in sufficient concentrations to form functional polypeptides. We ask how this subset, postulated as {A,D,E,G,I,L,P,S,T,V}, could have formed structures stable enough to found metabolic pathways. Inspired by alphabet reduction experiments, we undertook a computational analysis to measure the structural coding behavior of sequences simplified by reduced alphabets. We sought to discern characteristics of the prebiotic set that would endow it with unique properties relevant to structure, stability, and folding.

Results

Drawing on a large dataset of single-domain proteins, we employed an information-theoretic measure …


An Early Modern Human Outside Africa, Eric Delson Jul 2019

An Early Modern Human Outside Africa, Eric Delson

Publications and Research

Analysis of two fossils from a Greek cave has shed light on early hominins in Eurasia. One fossil is the earliest known specimen of Homo sapiens found outside Africa; the other is a Neanderthal who lived 40,000 years later.


Hiding In The Lianas Of The Tree Of Life: Molecular Phylogenetics And Species Delimitation Reveal Considerable Cryptic Diversity Of New World Vine Snakes, Robert C. Jadin, Christopher Blair, Michael J. Jowers, Anthony Carmona, John C. Murphy May 2019

Hiding In The Lianas Of The Tree Of Life: Molecular Phylogenetics And Species Delimitation Reveal Considerable Cryptic Diversity Of New World Vine Snakes, Robert C. Jadin, Christopher Blair, Michael J. Jowers, Anthony Carmona, John C. Murphy

Publications and Research

The Brown Vine Snake, Oxybelis aeneus, is considered a single species despite the fact its distribution covers an estimated 10% of the Earth’s land surface, inhabiting a variety of ecosystems throughout North, Central, and South America and is distributed across numerous biogeographic barriers. Here we assemble a multilocus molecular dataset (i.e. cyt b, ND4, cmos, PRLR) derived from Middle American populations to examine for the first time the evolutionary history of Oxybelis and test for evidence of cryptic lineages using Bayesian and maximum likelihood criteria. Our divergence time estimates suggest that Oxybelis diverged from its sister genus, Leptophis …


Area And Distance From Mainland Affect In Different Ways Richness And Phylogenetic Diversity Of Snakes In Atlantic Forest Coastal Islands, José Thales Da Motta Portillo, Lilian Sayuri Ouchi-Melo, Lucas Batista Crivellari, Thiago Alves Lopes De Oliveira, Ricardo J. Sawaya, Leonardo Da Silva Duarte Mar 2019

Area And Distance From Mainland Affect In Different Ways Richness And Phylogenetic Diversity Of Snakes In Atlantic Forest Coastal Islands, José Thales Da Motta Portillo, Lilian Sayuri Ouchi-Melo, Lucas Batista Crivellari, Thiago Alves Lopes De Oliveira, Ricardo J. Sawaya, Leonardo Da Silva Duarte

Publications and Research

Aim: The Theory of Island Biogeography posits that ecological and evolutionary processes regulate species richness of isolated areas. We assessed the influences of an island area and distance from the mainland on species richness, phylogenetic diversity, and phylogenetic composition of snakes on coastal islands.

Location: Coastal islands of the megadiverse Atlantic Forest in southeastern Brazil.

Methods: We compiled the species composition of 17 coastal islands in southeastern Brazil. Species richness and phylogenetic diversity were calculated for each island. Phylogenetic composition was measured using principal coordinates of phylogenetic structure. We then employed generalized linear models to test the influence of …


Standards For Distribution Models In Biodiversity Assessments, Miguel B. Araújo, Robert P. Anderson, A. Márcia Barbosa, Colin M. Beale, Carsten F. Dormann, Regan Early, Raquel A. Garcia, Antoine Guisan, Luigi Maiorano, Babak Naimi, Robert B. O'Hara, Niklaus E. Zimmermann, Carsten Rahbek Jan 2019

Standards For Distribution Models In Biodiversity Assessments, Miguel B. Araújo, Robert P. Anderson, A. Márcia Barbosa, Colin M. Beale, Carsten F. Dormann, Regan Early, Raquel A. Garcia, Antoine Guisan, Luigi Maiorano, Babak Naimi, Robert B. O'Hara, Niklaus E. Zimmermann, Carsten Rahbek

Publications and Research

Demand for models in biodiversity assessments is rising, but which models are adequate for the task? We propose a set of best-practice standards and detailed guidelines enabling scoring of studies based on species distribution models for use in biodiversity assessments. We reviewed and scored 400 modeling studies over the past 20 years using the proposed standards and guidelines. We detected low model adequacy overall, but with a marked tendency of improvement over time in model building and, to a lesser degree, in biological data and model evaluation. We argue that implementation of agreed-upon standards for models in biodiversity assessments would …


Social Learning Through Associative Processes: A Computational Theory, Johan Lind, Stefano Ghirlanda, Magnus Enquist Jan 2019

Social Learning Through Associative Processes: A Computational Theory, Johan Lind, Stefano Ghirlanda, Magnus Enquist

Publications and Research

Social transmission of information is a key phenomenon in the evolution of behaviour and in the establishment of traditions and culture. The diversity of social learning phenomena has engendered a diverse terminology and numerous ideas about underlying learning mechanisms, at the same time that some researchers have called for a unitary analysis of social learning in terms of associative processes. Leveraging previous attempts and a recent computational formulation of associative learning, we analyse the following learning scenarios in some generality: learning responses to social stimuli, including learning to imitate; learning responses to non-social stimuli; learning sequences of actions; learning to …


Local Adaptation In Mainland Anole Lizards: Integrating Population History And Genome–Environment Associations, Ivan Prates, Anna Penna, Miguel Trefaut Rodrigues, Ana Carolina Carnaval Nov 2018

Local Adaptation In Mainland Anole Lizards: Integrating Population History And Genome–Environment Associations, Ivan Prates, Anna Penna, Miguel Trefaut Rodrigues, Ana Carolina Carnaval

Publications and Research

Environmental gradients constrain physiological performance and thus species’ ranges, suggesting that species occurrence in diverse environments may be associated with local adaptation. Genome–environment association analyses (GEAA) have become central for studies of local adaptation, yet they are sensitive to the spatial orientation of historical range expansions relative to landscape gradients. To test whether potentially adaptive genotypes occur in varied climates in wide‐ranged species, we implemented GEAA on the basis of genomewide data from the anole lizards Anolis ortonii and Anolis punctatus, which expanded from Amazonia, presently dominated by warm and wet settings, into the cooler and less rainy Atlantic …


The Transcriptome Of The Bermuda Fireworm Odontosyllis Enopla (Annelida: Syllidae): A Unique Luciferase Gene Family And Putative Epitoky-Related Genes, Mercer R. Brugler, M. Teresa Aguado, Michael Tessler, Mark Siddall Aug 2018

The Transcriptome Of The Bermuda Fireworm Odontosyllis Enopla (Annelida: Syllidae): A Unique Luciferase Gene Family And Putative Epitoky-Related Genes, Mercer R. Brugler, M. Teresa Aguado, Michael Tessler, Mark Siddall

Publications and Research

The Bermuda fireworm Odontosyllis enopla exhibits an extremely tight circalunar circadian behavior that results in an impressive bioluminescent mating swarm, thought to be due to a conventional luciferase-mediated oxidation of a light-emitting luciferin. In addition, the four eyes become hypertrophied and heavily pigmented, and the nephridial system is modified to store and release gametes and associated secretions. In an effort to elucidate transcripts related to bioluminescence, circadian or circalunar periodicity, as well as epitoky-related changes of the eyes and nephridial system, we examined the transcriptomic profile of three female O. enopladuring a bioluminescent swarm in Ferry Reach, Bermuda. …


Forest Drought Resistance Distinguished By Canopy Height, Wei Fang, Peipei Xu, Tao Zhou, George Hendrey, Xiang Zhao Jun 2018

Forest Drought Resistance Distinguished By Canopy Height, Wei Fang, Peipei Xu, Tao Zhou, George Hendrey, Xiang Zhao

Publications and Research

How are the survival and growth of trees under severe drought affected by their size? While some studies have shown that large trees are more vulnerable to drought than smaller trees, others found that small trees are the more vulnerable. We explored the potential relationships between canopy height and forest responses to drought indicated by tree mortality, tree ring width index (RWI), and normalized difference vegetation index (NDVI) in the southwestern United States (SWUS) in 2002. In that year many trees had zero tree ring growth due to mortality and dieback, presumably related to drought-stress. With RWI data from a …


Anchored Phylogenomics Illuminates The Skipper Butterfly Tree Of Life, Emmanuel F. A. Toussaint, Jesse W. Breinholt, Chandra Earl, Andrew D. Warren, Andrew V. Z. Brower, Masaya Yago, Kelly M. Dexter, Marianne Espeland, Naomi E. Pierce, David J. Lohman, Akito Y. Kawahara Jun 2018

Anchored Phylogenomics Illuminates The Skipper Butterfly Tree Of Life, Emmanuel F. A. Toussaint, Jesse W. Breinholt, Chandra Earl, Andrew D. Warren, Andrew V. Z. Brower, Masaya Yago, Kelly M. Dexter, Marianne Espeland, Naomi E. Pierce, David J. Lohman, Akito Y. Kawahara

Publications and Research

Background: Butterflies (Papilionoidea) are perhaps the most charismatic insect lineage, yet phylogenetic relationships among them remain incompletely studied and controversial. This is especially true for skippers (Hesperiidae), one of the most species-rich and poorly studied butterfly families.

Methods: To infer a robust phylogenomic hypothesis for Hesperiidae, we sequenced nearly 400 loci using Anchored Hybrid Enrichment and sampled all tribes and more than 120 genera of skippers. Molecular datasets were analyzed using maximum-likelihood, parsimony and coalescent multi-species phylogenetic methods.

Results: All analyses converged on a novel, robust phylogenetic hypothesis for skippers. Different optimality criteria and methodologies recovered almost …