Genetics and Genomics Commons^™

Comparative Population Genomics And Speciation Of Snakes Across The North American Deserts, Edward A. Myers

Dissertations, Theses, and Capstone Projects

Understanding the process of speciation is of central interest to evolutionary biologists. Speciation can be studied using a phylogeographic approach, by identifying regions that promote lineage divergence, addressing whether speciation has occurred with gene flow, and when extended to multiple taxa, addressing if the same patterns of speciation are shared across codistributed groups with different ecologies. Here I examine the comparative phylogeographic histories and population genomics of thirteen snake taxa that are widely distributed and co-occur across the arid southwest of North America. I first quantify the degree to which these species groups have a shared history of population divergence …

Metabolic Profiling And Polymer Formation Of Gene Silenced Potato Periderms, Qing Cai

Dissertations, Theses, and Capstone Projects

Suberin is a biopolyester constituent of specialized plant periderm tissues formed within the phellem cell walls. Suberin and waxes of the periderm layer act to prevent water diffusion, mechanical breakdown and pathogenic invasion in plants. Ferulic esters, ω-hydroxyacids and α,ω-fatty diacids are considered to be the most important linkage between aliphatic and aromatic suberin domains and also linked with cell-wall polysaccharides. The potato gene FHT (fatty ω- hydroxyacid/fatty alcohol hydroxycinnamoyl transferase) esterifies ferulic acid to suberin. Diminished levels of feruloyl transferase activity have been associated with lowered amounts of feruloyl esters of fatty acids in both suberin-associated waxes and suberin …

The Regulation Of The Phosphatidate Phosphatase Gene Pah1 And Its Regulatory Role On Cell Homeostasis, Goldie Libby Sherr

Dissertations, Theses, and Capstone Projects

The Saccharomyces cerevisiae gene, PAH1, encodes a phosphatidate (PA) phosphatase that plays a fundamental role in lipid metabolism. PA phosphatases are key enzymes that catalyze the PA dephosphorylation reaction to form diacylglycerides, the first step in the synthesis of triacylglycerols. Pah1p, one of the main PA phosphatases in yeast, has not only emerged as a key player in lipid biosynthetic pathways, but also acts as an important regulator of nuclear membrane biogenesis, the transcriptional regulation of many inositol-sensitive upstream activating sequence (UAS_INO)containing genes needed for phospholipid synthesis, vacuole homeostasis, and lipid droplet formation. Due to its …

Phylogeny, Systematics And Biogeography Of Short-Tailed Opossums (Didelphidae: Monodelphis), Silvia E. Pavan

Dissertations, Theses, and Capstone Projects

Short-tailed opossums (genus Monodelphis) comprise the most species-rich genus of New World marsupials, with 25 currently recognized species. Monodelphis comprise small, terrestrial species collectively widespread in South America, which makes the group potentially informative about biogeographic processes that have shaped the continental fauna. The genus exhibits striking variation in several phenotypic characters, notably pelage coloration, behavior, and reproductive strategies. This diversity is unique among Neotropical marsupials, and makes the group particularly interesting to investigate the evolution and the adaptive significance of phenotypic trait variation. Despite this potential, missing knowledge on phylogeny and basic taxonomy precludes broader studies on evolution …

Machine Learning Meta-Analysis Of Large Metagenomic Datasets: Tools And Biological Insight, Edoardo Pasolli, Duy Tin Truong, Faizan Malik, Levi Waldron, Nicola Segata

Publications and Research

Shotgun metagenomic analysis of the human associated microbiome provides a rich set of microbial features for prediction and biomarker discovery in the context of human diseases and health conditions. However, the use of such high-resolution microbial features presents new challenges, and validated computational tools for learning tasks are lacking. Moreover, classification rules have scarcely been validated in independent studies, posing questions about the generality and generalization of disease-predictive models across cohorts. In this paper, we comprehensively assess approaches to metagenomics-based prediction tasks and for quantitative assessment of the strength of potential microbiome-phenotype associations. We develop a computational framework for prediction …

Comparative Genomics Explains The Evolutionary Success Of Reef-Forming Corals, Debashish Bhattacharya, Shobhit Agrawal, Manuel Aranda, Sebastian Baumgarten, Mahdi Belcaid, Jeana L. Drake, Douglas Erwin, Sylvian Foret, Ruth D. Gates, David F. Gruber, Bishoy Kamel, Michael P. Lesser, Oren Levy, Yi Jin Liew, Matthew Macmanes, Tali Mass, Monica Medina, Shaadi Mehr, Eli Meyer, Dana C. Price, Hollie M. Putnam, Huan Qiu, Chuya Shinzato, Eiichi Shoguchi, Alexander J. Stokes, Sylvie Tambutté, Dan Tchernov, Christian R. Voolstra, Nicole Wagner, Charles W. Walker, Andreas Pm Weber, Virginia Weis, Ehud Zelzion, Didier Zoccola, Paul G. Falkowski

Publications and Research

Transcriptome and genome data from twenty stony coral species and a selection of reference bilaterians were studied to elucidate coral evolutionary history. We identified genes that encode the proteins responsible for the precipitation and aggregation of the aragonite skeleton on which the organisms live, and revealed a network of environmental sensors that coordinate responses of the host animals to temperature, light, and pH. Furthermore, we describe a variety of stress-related pathways, including apoptotic pathways that allow the host animals to detoxify reactive oxygen and nitrogen species that are generated by their intracellular photosynthetic symbionts, and determine the fate of corals …

Epigenetic Profiles Signify Cell Fate Plasticity In Unipotent Spermatogonial Stem And Progenitor Cells, Ying Liu, Eugenia G. Giannopoulou, Duacheng Wen, Ilaria Falciatori, Oliver Elemento, C. David Allis, Shahin Rafii, Marco Seandel

Publications and Research

Spermatogonial stem and progenitor cells (SSCs) generate adult male gametes. During in vitro expansion, these unipotent murine cells spontaneously convert to multipotent adult spermatogonial-derived stem cells (MASCs). Here we investigate this conversion process through integrative transcriptomic and epigenomic analyses. We find in SSCs that promoters essential to maintenance and differentiation of embryonic stem cells (ESCs) are enriched with histone H3-lysine4 and -lysine 27 trimethylations. These bivalent modifications are maintained at most somatic promoters after conversion, bestowing MASCs an ESC-like promoter chromatin. At enhancers, the core pluripotency circuitry is activated partially in SSCs and completely in MASCs, concomitant with loss of …

Comparative Error-Free And Error-Prone Translesion Synthesis Of N2‑2′-Deoxyguanosine Adducts Formed By Mitomycin C And Its Metabolite, 2,7-Diaminomitosene, In Human Cells, Arindam Bose, Chaitra Surugihalli, Paritosh Pande, Elise Champeil, Ashis K. Basu

Publications and Research

Mitomycin C (MC) is a cytotoxic and mutagenic antitumor agent that alkylates DNA upon reductive activation. 2,7-Diaminomitosene (2,7-DAM) is a major metabolite of MC in tumor cells, which also alkylates DNA. MC forms seven DNA adducts, including monoadducts and inter- and intrastrand cross-links, whereas 2,7-DAM forms two monoadducts. Herein, the biological effects of the dG-N2 adducts formed by MC and 2,7-DAM have been compared by constructing single-stranded plasmids containing these adducts and replicating them in human embryonic kidney 293T cells. Translesion synthesis (TLS) efficiencies of dG-N2-MC and dG-N2-2,7-DAM were 38 ± 3 and 27 …

Effects Of Choline On Dna Methylation And Macronutrient Metabolic Gene Expression In In Vitro Models Of Hyperglycemia, Xinyin Jiang, Esther Greenwald, Chauntelle Jack-Roberts

Publications and Research

Choline is an essential nutrient that plays an important role in lipid metabolism and DNA methylation. Studies in rodents suggest that choline may adversely affect glycemic control, yet studies in humans are lacking. Using the human hepatic and placental cells, HepG2 and BeWo, respectively, we examined the interaction between choline and glucose treatments. In HepG2 cells, choline supplementation (1 mM) increased global DNA methylation and DNA methyltransferase expression in both low-glucose (5 mM) and high-glucose (35 mM) conditions. Choline supplementation increased the expression of peroxisomal acyl-coenzyme A oxidase 1 (ACOX1), which mediates fatty acid β-oxidation, especially in the high-glucose condition. …

Diversity-Dependent Cladogenesis Throughout Western Mexico: Evolutionary Biogeography Of Rattlesnakes (Viperidae: Crotalinae: Crotalus And Sistrurus), Christopher Blair, Santiago Sánchez-Ramírez

Publications and Research

Rattlesnakes (Crotalus and Sistrurus) represent a radiation of approximately 42 species distributed throughout the New World from southern Canada to Argentina. Interest in this enigmatic group of snakes continues to accrue due, in part, to their ecomorphological diversity, contributions to global envenomations, and potential medicinal importance. Although the group has garnered substantial attention from systematists and evolutionary biologists for decades, little is still known regarding patterns of lineage diversification. In addition, few studies have statistically quantified broad-scale biogeographic patterns in rattlesnakes to ascertain how dispersal occurred throughout the New World, particularly among the different major biomes of the …

Genome Assembly And Geospatial Phylogenomics Of The Bed Bug Cimex Lectularius, Jeffrey A. Rosenfeld, Darryl Reeves, Mercer R. Brugler, Apurva Narechania, Sabrina Simon, Russell Durrett, Jonathan Foox, Kevin Shianna, Michael C. Schatz, Jorge Gandara, Ebrahim Afshinnekoo, Ernest T. Lam, Alex R. Hastie, Saki Chan, Han Cao, Michael Saghbini, Alex Kentsis, Paul J. Planet, Vladyslav Kholodovych, Michael Tessler, Richard Baker, Rob Desalle, Louis N. Sorkin, Sergios-Orestis Kolokotronis, Mark E. Siddall, George Amato, Christopher E. Mason

Publications and Research

The common bed bug (Cimex lectularius) has been a persistent pest of humans for thousands of years, yet the genetic basis of the bed bug’s basic biology and adaptation to dense human environments is largely unknown. Here we report the assembly, annotation and phylogenetic mapping of the 697.9-Mb Cimex lectularius genome, with an N50 of 971 kb, using both long and short read technologies. A RNA-seq time course across all five developmental stages and male and female adults generated 36,985 coding and noncoding gene models. The most pronounced change in gene expression during the life cycle occurs after feeding on …

The Evolution Of The Viral Rna Sensor Oas1 In Old World Monkeys And Cetartiodactyls, Ian Fish

Dissertations, Theses, and Capstone Projects

Animals produce an array of sensors patrolling the intracellular environment poised to detect and respond to viral infection. The oligoadenylate synthetase family of enzymes comprises a crucial part of this innate immune response, directly signaling endonuclease activity responsible for inhibiting viral replication. Oligoadenylate synthetase 1 plays a vital role in animal susceptibility to pathogens including flaviviruses such as dengue, West Nile, and hepatitis c virus. This thesis includes a population level analysis of OAS1 diversity within macaque and baboon species followed by a broader survey of the gene in nineteen Old World monkeys. My research found that at the species …

Lim Protein Ajuba Participates In The Repression Of Atr-Mediated Dna Damage Response In Human Cells, Sampada Kalan

Dissertations, Theses, and Capstone Projects

LIM proteins constitute a superfamily characterized by the presence of specialized domains called LIM. LIM domain is a unique double-zinc finger motif found in a variety of proteins and is mainly involved in protein-protein interactions. Previous work has implicated that members of the Zyxin subfamily of LIM proteins, namely TRIP6 and LPP are involved in the repression of the DNA damage response (DDR) at telomeres. We further explore if another member from this family has an influence on DDR prevention in the cells. Here, we describe a novel role for Ajuba, a Zyxin family LIM protein, in repressing inappropriate activation …

Role Of Bec-1/Beclin 1 And Autophagy Genes In C.Elegans Germline Cell Proliferation, Kristina Ames

Dissertations, Theses, and Capstone Projects

Autophagy is an evolutionary conserved process involved in the cellular adaptation to stress and basal levels of autophagy are crucial for cellular metabolism and homeostasis. Cellular recycling by autophagy is characterized by the formation of distinctive double-membrane vesicles (autophagosomes) that engulf unnecessary cytoplasmic components, such as organelles and long-lived proteins. Failure to remove protein aggregates and/or damaged organelles, via autophagy, has been implicated in various medical conditions such as liver disease, neurodegenerative diseases and cancer. Autophagy may suppress or promote cellular proliferation in tumors, depending on the type and metabolic state of the cell, where autophagy is generally believed to …

The Implications Of Chromatin Remodelers' Acetylation In Ino1 Activation, Michelle M. Esposito

Dissertations, Theses, and Capstone Projects

It is known that histone acetylases (HATs) regulate gene expression, but only recently have new functional implications about remodelers’ acetylation emerged. For instance, the HAT, Gcn5p, is capable of acetylating the catalytic subunit of the nucleosome remodeling complex SWI/SNF, Snf2p, which results in the dissociation of the complex from chromatin. The implications of this acetylation and subsequent dissociation have yet to be explored with regard to transcriptional regulation and other possible mechanisms. To further understand the implications of remodeler acetylation, I used a yeast model system examining the expression of the inositol-3-phosphate synthase gene INO1. Through chromatin immunoprecipitation (ChIP) …

Cellmapper: Rapid And Accurate Inference Of Gene Expression In Difficult-To-Isolate Cell Types, Bradlee D. Nelms, Levi Waldron, Luis A. Barrera, Andrew W. Weflen, Jeremy A. Goettel, Guoji Guo, Robert K. Montgomery, Marian R. Neutra, David T. Breault, Scott B. Snapper, Stuart H. Orkin, Martha L. Bulyk, Curtis Huttenhower, Wayne I. Lencer

Publications and Research

We present a sensitive approach to predict genes expressed selectively in specific cell types, by searching publicly available expression data for genes with a similar expression profile to known cell-specific markers. Our method, CellMapper, strongly outperforms previous computational algorithms to predict cell type-specific expression, especially for rare and difficult-to-isolate cell types. Furthermore, CellMapper makes accurate predictions for human brain cell types that have never been isolated, and can be rapidly applied to diverse cell types from many tissues. We demonstrate a clinically relevant application to prioritize candidate genes in disease susceptibility loci identified by GWAS.

The Mitogenome Of The Bed Bug Cimex Lectularius (Hemiptera: Cimicidae), Sergios-Orestis Kolokotronis, Jonathan Foox, Jeffrey A. Rosenfeld, Mercer R. Brugler, Darryl Reeves, Joshua B. Benoit, Warren Booth, Grant Robison, Michael Steffen, Zoe Sakas, Subba R. Palli, Coby Schal, Stephen Richards, Apurva Narechania, Richard H. Baker, Louis N. Sorkin, George Amato, Christopher E. Mason, Mark E. Siddall, Rob Desalle

Publications and Research

We report the extraction of a bed bug mitogenome from high-throughput sequencing projects originally focused on the nuclear genome of Cimex lectularius. The assembled mitogenome has a similar AT nucleotide composition bias found in other insects. Phylogenetic analysis of all protein-coding genes indicates that C. lectularius is clearly a member of a paraphyletic Cimicomorpha clade within the Order Hemiptera.

Special Muscles, Annamaria C. Scaccia

Capstones

Special Muscles is a documentary that explores living with Duchenne muscular dystrophy, a fatal degenerative disease that weakens the muscles at an aggressive rate. The film will give an uncensored look at how one family copes with inevitability of the disease and their journey chasing a promising experimental cure.

Special Muscles follows 7-year-old Pietro Scarso and his family as they face the challenges, complications and promise of treating Pietro’s progressive muscle disorder. The film travels from New York to Los Angeles to Philadelphia to document the Scarso family’s race against time as Pietro undergoes a 96-week clinical trial for Eteplirsen, …

Elimination Of Chromosomal Island Spycim1 From Streptococcus Pyogenes Strain Sf370 Reverses The Mutator Phenotype And Alters Global Transcription, Christina Hendrickson, Chad W. Euler, Scott V. Nguyen, Maliha Rahman, Kimberly A. Mccullor, Catherine J. King, Vincent A. Fischetti, W. Michael Mcshan

Publications and Research

Streptococcus pyogenes chromosomal island M1 (SpyCIM1) integrates by site-specific recombination into the 5’ end of DNA mismatch repair (MMR) gene mutL in strain SF370SmR, blocking transcription of it and the downstream operon genes. During exponential growth, SpyCIM1 excises from the chromosome and replicates as an episome, restoring mutL transcription. This process is reversed in stationary phase with SpyCIM1 re-integrating into mutL, returning the cells to a mutator phenotype. Here we show that elimination of SpyCIM1 relieves this mutator phenotype. The downstream MMR operon genes, multidrug efflux pump lmrP, Holliday junction resolution helicase ruvA, and DNA base excision …

The Insulin/Igf Signaling Regulator Cytohesin/Grp-1 Modulates Sensitivity To Excitotoxicity In C. Elegans, Nazila Tehrani

Dissertations, Theses, and Capstone Projects

Excitotoxicity is a form of neurodegeneration that serves as the main underlying cause of brain damage in stroke/brain ischemia, and a contributing factor in a range of neurological diseases such as Epilepsy, ALS, Alzheimer, and Huntington's disease. In excitotoxicity, over-activation of glutamate receptors causes necrotic neuronal cell death. In spite of intense study of excitotoxicity, the molecular mechanisms that lead from glutamate receptor activation to necrotic death remain a mystery. Aging neurons are known to be more vulnerable to excitotoxicity and less likely to recover, but the underlying reasons for the increased cellular vulnerability are unknown. To gain insight into …

Molecular-Genetic And Behavioral Analysis Of The Functionality Of Patterning In The Trigeminal Neuraxis, Dana Bakalar

Dissertations, Theses, and Capstone Projects

A striking feature of the vibrissal representation in rodents is the presence; at brainstem (barrellettes), thalamic (barrelloids) and cortical levels (barrels) of a somatotopically organized pattern of neurons which is isomorphic, both morphologically and physiologically, to the pattern of vibrissae on the snout. The vibrissal system is required for several classes of behavior, including feeding and active vibrissal sensing, but the functional role of the patterning in these behaviors is unknown. We used two mutant animals lacking patterning in two areas of the vibrissal neuraxis to examine the functional role of patterning. We examined feeding behavior using a knockout of …

Dna Methylation Dynamics Of Germinal Center B Cells Are Mediated By Aid, Pilar M. Dominguez, Matt Teater, Nyasha Chambwe, Matthias Kormaksson, David Redmon, Jennifer Ishii, Bao Vuong, Jayanta Chaudhuri, Ari Melnick, Aparna Vasanthakumar, Lucy A. Godley, F. Nina Papavasiliou, Oliver Elemento, Rita Shaknovich

Publications and Research

Changes in DNA methylation are required for the formation of germinal centers (GCs), but the mechanisms of such changes are poorly understood. Activation-induced cytidine deaminase (AID) has been recently implicated in DNA demethylation through its deaminase activity coupled with DNA repair. We investigated the epigenetic function of AID in vivo in germinal center B cells (GCBs) isolated from wild-type (WT) and AID-deficient (Aicda^−/−) mice. We determined that the transit of B cells through the GC is associated with marked locus-specific loss of methylation and increased methylation diversity, both of which are lost in Aicda^−/− animals. Differentially …

Population Genetic Structure Of The Dwarf Seahorse (Hippocampus Zosterae) In Florida, Nathan Fedrizzi, Melanie L. J. Stiassny, J. T. Boehm, Eric R. Dougherty, George Amato, Martin Mendez

Publications and Research

The dwarf seahorse (Hippocampus zosterae) is widely distributed throughout near-shore habitats of the Gulf of Mexico and is of commercial significance in Florida, where it is harvested for the aquarium and curio trades. Despite its regional importance, the genetic structure of dwarf seahorse populations remains largely unknown. As an aid to ongoing conservation efforts, we employed three commonly applied mtDNA markers (ND4, DLoop and CO1) to investigate the genetic structuring of H. zosterae in Florida using samples collected throughout its range in the state. A total of 1450 bp provided sufficient resolution to delineate four populations of dwarf seahorses, as …

Transcriptome Sequencing And Annotation Of The Polychaete Hermodice Carunculata (Annelida, Amphinomidae), Shaadi Mehr, Aida Verdes, Rob Desalle, John S. Sparks, Vincent A. Pieribone, David F. Gruber

Publications and Research

Background: The amphinomid polychaete Hermodice carunculata is a cosmopolitan and ecologically important omnivore in coral reef ecosystems, preying on a diverse suite of reef organisms and potentially acting as a vector for coral disease. While amphinomids are a key group for determining the root of the Annelida, their phylogenetic position has been difficult to resolve, and their publically available genomic data was scarce.

Results: We performed deep transcriptome sequencing (Illumina HiSeq) and profiling on Hermodice carunculata collected in the Western Atlantic Ocean. We focused this study on 58,454 predicted Open Reading Frames (ORFs) of genes longer than 200 amino acids …

Phylogenomic Identification Of Regulatory Sequences In Bacteria: An Analysis Of Statistical Power And An Application To Borrelia Burgdorferi Sensu Lato, Che I. Martin, Tika Y. Sukarna, Saymon Akther, Girish Ramrattan, Pedro Pagan, Lia Di, Emmanuel F. Mongodin, Claire M. Fraser, Steven E. Schutzer, Benjamin J. Luft, Sherwood R. Casjens, Wei-Gang Qiu

Publications and Research

Phylogenomic footprinting is an approach for ab initio identification of genome-wide regulatory elements in bacterial species based on sequence conservation. The statistical power of the phylogenomic approach depends on the degree of sequence conservation, the length of regulatory elements, and the level of phylogenetic divergence among genomes. Building on an earlier model, we propose a binomial model that uses synonymous tree lengths as neutral expectations for determining the statistical significance of conserved intergenic spacer (IGS) sequences. Simulations show that the binomial model is robust to variations in the value of evolutionary parameters, including base frequencies and the transition-to-transversion ratio. We …

Associations Between Host Gene Expression, The Mucosal Microbiome, And Clinical Outcome In The Pelvic Pouch Of Patients With Inflammatory Bowel Disease, Xochitl C. Morgan, Boyko Kabakchiev, Levi Waldron, Andrea D. Tyler, Timothy L. Tickle, Raquel Milgrom, Joanne M. Stempak, Dirk Gevers, Ramnik J. Xavier, Mark S. Silverberg, Curtis Huttenhower

Publications and Research

Background: Pouchitis is common after ileal pouch-anal anastomosis (IPAA) surgery for ulcerative colitis (UC). Similar to inflammatory bowel disease (IBD), both host genetics and the microbiota are implicated in its pathogenesis. We use the IPAA model of IBD to associate mucosal host gene expression with mucosal microbiomes and clinical outcomes. We analyze host transcriptomic data and 16S rRNA gene sequencing data from paired biopsies from IPAA patients with UC and familial adenomatous polyposis. To achieve power for a genome-wide microbiome-transcriptome association study, we use principal component analysis for transcript and clade reduction, and identify significant co-variation between clades and transcripts. …

Historical And Contemporary Demography Of Leaf-Toed Geckos (Phyllodactylidae: Phyllodactylus) In The Mexican Dry Forest, Christopher Blair, Victor H. Jiménez Arcos, Fausto R. Méndez De La Cruz, Robert W. Murphy

Publications and Research

Disentangling the relative influence of historical versus contemporary processes shaping the spatial distribution of genetic variation is critical if we are to effectively mitigate key biodiversity issues. We utilize a comprehensive approach based on different molecular marker types and analytical methods to understand the demographic consequences of recent habitat fragmentation in a spatially explicit context. We focus our efforts on native leaf-toed geckos (Phyllodactylus tuberculosus saxatilis) throughout fragmented habitat in the tropical dry forest of northern Mexico as recent evidence suggests that geographic ranges for these geckos may be much smaller than currently realized. However, no data are …

Improved Evidence-Based Genome-Scale Metabolic Models For Maize Leaf, Embryo, And Endosperm, Samuel M. D. Seaver, Louis M. T. Bradbury, Océane Frelin, Raphy Zarecki, Eytan Ruppin, Andrew D. Hanson, Christopher S. Henry

Publications and Research

There is a growing demand for genome-scale metabolic reconstructions for plants, fueled by the need to understand the metabolic basis of crop yield and by progress in genome and transcriptome sequencing. Methods are also required to enable the interpretation of plant transcriptome data to study how cellular metabolic activity varies under different growth conditions or even within different organs, tissues, and developmental stages. Such methods depend extensively on the accuracy with which genes have been mapped to the biochemical reactions in the plant metabolic pathways. Errors in these mappings lead to metabolic reconstructions with an inflated number of reactions and …

High-Throughput Comparison, Functional Annotation, And Metabolic Modeling Of Plant Genomes Using The Plantseed Resource, Samuel M. D. Seaver, Svetlana Gerdes, Océane Frelin, Claudia Lerma-Ortiz, Louis M. T. Bradbury, Rémi Zallot, Ghulam Hasnain, Thomas D. Niehaus, Basma El Yacoubi, Shiran Pasternak, Robert Olson, Gordon Pusch, Ross Overbeek, Valérie De Crécy-Lagarde, Doreen Ware, Andrew D. Hanson, Christopher S. Henry

Publications and Research

There is a growing demand for genome-scale metabolic reconstructions for plants, fueled by the need to understand the metabolic basis of crop yield and by progress in genome and transcriptome sequencing. Methods are also required to enable the interpretation of plant transcriptome data to study how cellular metabolic activity varies under different growth conditions or even within different organs, tissues, and developmental stages. Such methods depend extensively on the accuracy with which genes have been mapped to the biochemical reactions in the plant metabolic pathways. Errors in these mappings lead to metabolic reconstructions with an inflated number of reactions and …

Revisiting The Vanishing Refuge Model Of Diversification, Robert Damasceno, Maria L. Strangas, Ana C. Carnaval, Miguel T. Rodrigues, Craig Moritz

Publications and Research

Much of the debate around speciation and historical biogeography has focused on the role of stabilizing selection on the physiological (abiotic) niche, emphasizing how isolation and vicariance, when associated with niche conservatism, may drive tropical speciation. Yet, recent re-emphasis on the ecological dimensions of speciation points to a more prominent role of divergent selection in driving genetic, phenotypic, and niche divergence. The vanishing refuge model (VRM), first described by Vanzolini and Williams (1981), describes a process of diversification through climate-driven habitat fragmentation and exposure to new environments, integrating both vicariance and divergent selection. This model suggests that dynamic climates and …