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Full-Text Articles in Genetics and Genomics

Understanding The Impacts Of Current And Future Environmental Variation On Central African Amphibian Biodiversity, Courtney A. Miller Dec 2018

Understanding The Impacts Of Current And Future Environmental Variation On Central African Amphibian Biodiversity, Courtney A. Miller

LSU New Orleans Theses and Dissertations

Global climate change is projected to impact multiple levels of biodiversity by imposing strong selection pressures on existing populations, triggering shifts in species distributions, and reorganizing entire communities. The Lower Guineo-Congolian region in central Africa, a reservoir for amphibian diversity, is predicted to be severely affected by future climate change through rising temperatures and greater variability in rainfall. Geospatial modelling can be used to assess how environmental variation shapes patterns of biological variation – from the genomic to the community level – and use these associations to predict patterns of biological change across space and time. The overall goal of …


Red Panda: A Novel Method For Detecting Variation In Single-Cell Rna Sequencing, Adam Cornish Dec 2018

Red Panda: A Novel Method For Detecting Variation In Single-Cell Rna Sequencing, Adam Cornish

Theses & Dissertations

Single-cell sequencing enables the rapid acquisition of genomic and transcriptomic data from individual cells to better understand genetic diseases, such as cancer or autoimmune disorders, which are often affected by changes in rare cells. Currently, no existing software is aimed at identifying single nucleotide variations or micro (1-50bp) insertions and deletions in single-cell RNA sequencing (scRNA-seq) data. However, generating high quality data is vital to the study of the aforementioned diseases, among others. Our goal is to create such a tool and use in-house sequencing to validate its effectiveness. Our software employs the unique information found in scRNA-seq data to …


Physella Acuta, Comparative Immunology And Evolutionary Aspects Of Gastropod Immune Function, Jonathan H. Schultz Dec 2018

Physella Acuta, Comparative Immunology And Evolutionary Aspects Of Gastropod Immune Function, Jonathan H. Schultz

Biology ETDs

Gastropod immunobiology has benefitted from investigations focused on the planorbid snail Biomphalaria glabrata, intermediate host for the human parasite Schistosoma mansoni. Though such concentrated efforts have elucidated fascinating aspects of invertebrate immunity, they have not provided full knowledge regarding the evolution of immune function among other gastropod species. This dissertation presents the importance of making strategic choices regarding which organisms to select for comparative immunology. Herein, the choice was made to investigate the immunobiology of Physella acuta, a freshwater snail species of the Physidae, a sister family to Planorbidae to which B. glabrata belongs. Benefiting greatly from …


Genetic And Epigenetic Investigations On Pulmonary Hypertension Syndrome In Meat Type- Chickens, Khaloud Alzahrani Dec 2018

Genetic And Epigenetic Investigations On Pulmonary Hypertension Syndrome In Meat Type- Chickens, Khaloud Alzahrani

Graduate Theses and Dissertations

This dissertation presents a collection of studies that investigate the genetic and epigenetic associations to ascites phenotype in broiler chickens. Ascites is a significant metabolic disease associated with fast-growing meat-type chickens (broilers) and is a terminal result of pulmonary hypertension syndrome PHS. It is a multi-factorial syndrome caused by interactions between genetic, physiological, environmental, and managemental factors. It was estimated that ascites accounts for losses of about US$1 billion annually worldwide and for over 25% of broilers mortality. Although traditional and molecular genetic methods in the selection and in performance improvements, has greatly reduced ascites frequency, yet it has not …


Improving Dbnsfp, Mingyao Lu Dec 2018

Improving Dbnsfp, Mingyao Lu

Dissertations and Theses (Open Access)

IMPROVING dbNSFP

Mingyao Lu, B.S.

Advisory Professor: Xiaoming Liu, Ph.D.

The analysis and interpretation of DNA variation are very important for the Whole Exome studies (WES). Genome research has focused on single nucleotide variants (SNVs). Since indels are as important as SNVs, especially indels in coding regions are often candidates of disease-causing variants, thus, it is necessary to expand the focus to include indel mutations.

The goal of my project is to provide an automatic annotation pipeline to the WES based disease studies project by extending the dbNSFP with a tool for automated indel annotation and deleteriousness prediction. The current …


How Does Antibiotic Resistance Spread In Tuberculosis?, Julie A. Spencer Nov 2018

How Does Antibiotic Resistance Spread In Tuberculosis?, Julie A. Spencer

Shared Knowledge Conference

The ancient bacterial disease of tuberculosis (TB) is curable with antibiotics, but according to the World Health Organization, in 2016 over 10 million people became infected with the disease. 600,000 of these cases were resistant to antibiotics, yet the worldwide treatment success rate for drug resistant TB is only 54%. Furthermore, strains exist now that are resistant to all known antibiotics. In the current environment of global travel, this poses a risk for emergent epidemics of drug resistant TB. In this study, I asked: after an antibiotic resistant strain has evolved in someone’s lungs, how does it spread? It is …


Mechanisms For The Spread Of Antibiotic Resistance In Tuberculosis, Julie Allison Spencer Nov 2018

Mechanisms For The Spread Of Antibiotic Resistance In Tuberculosis, Julie Allison Spencer

Shared Knowledge Conference

Tuberculosis (TB) is currently the ninth leading cause of death for humans worldwide, causing 10.4 million new infections in 2016. According to the World Health Organization, of these infections, 600,000 were antibiotic resistant. However, the treatment success rate for resistant TB was only 54%. The potential for emergent epidemics of drug resistant TB highlights the need to understand the mechanisms for the spread of resistance. Mycobacterium tuberculosis, the bacterium that causes TB, evolves resistant strains within individuals who are being treated with antibiotics. It has been assumed previously that the resistant characteristics of these strains are spread primarily by the …


Identification And Characterization Of Nitrogen Fixing Bacteria Associated With Kudzu Root Nodules, Chasity Lawless, Michelle Zedonek, Debbie Curtis, Jonda Scharringhausen, Jared Bryant, Wendy A. Dustman, Alexandra M. Kurtz, Bekah Ward Dr. Sep 2018

Identification And Characterization Of Nitrogen Fixing Bacteria Associated With Kudzu Root Nodules, Chasity Lawless, Michelle Zedonek, Debbie Curtis, Jonda Scharringhausen, Jared Bryant, Wendy A. Dustman, Alexandra M. Kurtz, Bekah Ward Dr.

Georgia Journal of Science

Pueraria montana, better known as kudzu, is an invasive species rapidly spreading throughout the southeastern United States. This plant can form root nodules which house nitrogen-fixing bacteria, allowing atmospheric nitrogen to be converted into biologically available forms of nitrogen for use by the plant host. Given the centrality of these bacteria to the spread of kudzu, isolates from nodules were characterized after collection from seven different locations across the metropolitan Atlanta area. Twenty-five isolates were grown on two different variants of nitrogen free media. Four different carbon sources were evaluated as well. Finally, growth under both aerobic and anaerobic …


Confirming World-Wide Distribution Of An Agriculturally Important Lacewing, Chrysoperla Zastrowi Sillemi, Using Songs, Morphology, Mitochondrial Gene Sequencing, And Phylogenetic Reconstruction, Zoe Mandese Aug 2018

Confirming World-Wide Distribution Of An Agriculturally Important Lacewing, Chrysoperla Zastrowi Sillemi, Using Songs, Morphology, Mitochondrial Gene Sequencing, And Phylogenetic Reconstruction, Zoe Mandese

Honors Scholar Theses

The Chrysoperla carnea-group of green lacewings is a cryptic species complex. Species within the group are morphologically similar, yet isolated from one another via reproductive mating song. Chrysoperla zastrowi, a species within the carnea-group, is currently described with a distribution ranging from South Africa to the Middle East and India. However, recent collections of carnea-group lacewings from Guatemala and California were preliminarily identified as Chrysoperla zastrowi based upon similarities in their vibrational courtship songs. This analysis aims to place six specimens, collected by collaborators in Guatemala, Armenia, Iran, and California, into a pre-existing phylogeny of the …


Microbial Ecology Of South Florida Surface Waters: Examining The Potential For Anthropogenic Influences, Chase P. Donnelly Aug 2018

Microbial Ecology Of South Florida Surface Waters: Examining The Potential For Anthropogenic Influences, Chase P. Donnelly

HCNSO Student Theses and Dissertations

South Florida contains one of the largest subtropical wetlands in the world, and yet not much is known about the microbes that live in these surface waters. These microbes play an important role in chemical cycling and maintaining good water quality for both human and ecosystem health. The hydrology of Florida’s surface waters is tightly regulated with the use of canal and levee systems run by the US Army Corps of Engineers and The South Florida Water Management District. These canals run through the Everglades, agriculture, and urban environments to control water levels in Lake Okeechobee, the Water Conservation Areas, …


Bayesian Analytical Approaches For Metabolomics : A Novel Method For Molecular Structure-Informed Metabolite Interaction Modeling, A Novel Diagnostic Model For Differentiating Myocardial Infarction Type, And Approaches For Compound Identification Given Mass Spectrometry Data., Patrick J. Trainor Aug 2018

Bayesian Analytical Approaches For Metabolomics : A Novel Method For Molecular Structure-Informed Metabolite Interaction Modeling, A Novel Diagnostic Model For Differentiating Myocardial Infarction Type, And Approaches For Compound Identification Given Mass Spectrometry Data., Patrick J. Trainor

Electronic Theses and Dissertations

Metabolomics, the study of small molecules in biological systems, has enjoyed great success in enabling researchers to examine disease-associated metabolic dysregulation and has been utilized for the discovery biomarkers of disease and phenotypic states. In spite of recent technological advances in the analytical platforms utilized in metabolomics and the proliferation of tools for the analysis of metabolomics data, significant challenges in metabolomics data analyses remain. In this dissertation, we present three of these challenges and Bayesian methodological solutions for each. In the first part we develop a new methodology to serve a basis for making higher order inferences in metabolomics, …


Deciphering The Role Of Human Arylamine N-Acetyltransferase 1 (Nat1) In Breast Cancer Cell Metabolism Using A Systems Biology Approach., Samantha Marie Carlisle Aug 2018

Deciphering The Role Of Human Arylamine N-Acetyltransferase 1 (Nat1) In Breast Cancer Cell Metabolism Using A Systems Biology Approach., Samantha Marie Carlisle

Electronic Theses and Dissertations

Background: Human arylamine N-acetyltransferase 1 (NAT1) is a phase II xenobiotic metabolizing enzyme found in almost all tissues. NAT1 can additionally hydrolyze acetyl-coenzyme A (acetyl-CoA) in the absence of an arylamine substrate. NAT1 expression varies inter-individually and is elevated in several cancers including estrogen receptor positive (ER+) breast cancers. Additionally, multiple studies have shown the knockdown of NAT1, by both small molecule inhibition and siRNA methods, in breast cancer cells leads to decreased invasive ability and proliferation and decreased anchorage-independent colony formation. However, the exact mechanism by which NAT1 expression affects cancer risk and progression remains unclear. Additionally, consequences …


Genomic And Transcriptomic Landscape Of Colorectal Premalignancy, Kyle Chang Aug 2018

Genomic And Transcriptomic Landscape Of Colorectal Premalignancy, Kyle Chang

Dissertations and Theses (Open Access)

Colorectal cancer (CRC) is the third most commonly diagnosed cancer among men and women in the United States, with 3 to 5 percent of the cases diagnosed in the background of a hereditary form of the disease. Biologically, CRC is divided into two groups: microsatellite instable (MSI) and chromosomally unstable (CIN). Genomic and transcriptomic characterization of CRC has emerged from large-scale studies in recent years due to the advancement of next-generation sequencing technologies. These studies have identified key genes and pathways altered in CRC and provided insights to the discovery of therapeutic targets. Despite the wealth of knowledge acquired in …


Omics Approaches To Uncover Germline And Somatic Variation Underlying Inherited Sarcomagenesis, Justin Wong Aug 2018

Omics Approaches To Uncover Germline And Somatic Variation Underlying Inherited Sarcomagenesis, Justin Wong

Dissertations and Theses (Open Access)

Sarcomas are rare mesenchymal tumors, making up 15% of all childhood and 1% of all adult tumors. They account for a disproportionate share of mortality in young adults, and if left untreated, are highly likely to metastasize. However, sarcoma etiology is poorly understood, and having numerous histological subtypes has complicated elucidation. To better understand factors underlying sarcomagenesis, we leveraged two rare inherited cancer predisposition syndromes, Li-Fraumeni Syndrome (LFS), and LFS-like (LFSL), both with a high incidence of sarcomas. LFS is caused by mutations in the tumor suppressor gene TP53 (p53), but has variable and incomplete penetrance, suggesting additional acquired …


Computational Analysis Of Genomic Variants Affecting Predicted Microrna:Target Interactions In Prostate Cancer., Angélica Paola Hernández Pérez Jul 2018

Computational Analysis Of Genomic Variants Affecting Predicted Microrna:Target Interactions In Prostate Cancer., Angélica Paola Hernández Pérez

KGI Theses and Dissertations

Prostate cancer (PCa) is the most common cancer of men in the United States and is third only to lung and colon as a cause of cancer death. Clinical behavior of the disease is variable and the combination of prostate-specific antigen (PSA) screening and Gleason score staging are currently the best available molecular and pathology tools to predict outcomes. Cancer biology research establishes microRNAs (miRNAs) as key molecular components in both normal and pathological states. Thus, elucidating miRNAs perturbed by genomic alterations will expand our understanding of the molecular taxonomy of PCa with the aim to complement current practices in …


Genomic Signatures Of Adaptive Evolution, Jessica A. Weber Jul 2018

Genomic Signatures Of Adaptive Evolution, Jessica A. Weber

Biology ETDs

Comparative genomics has revolutionized virtually all fields of biology including the study of evolution. In this dissertation, I used next-generation sequencing to explore the evolutionary histories and adaptive evolution of a diverse set of taxa. Comparisons ranged across time scales, from population-level genetic diversity studies to questions spanning the deepest branches of the metazoan lineage. Whole genome sequencing of 50 unrelated Korean individuals revealed that Koreans have a distinct genetic history from the Chinese and Japanese populations. Our Korean-specific variome database was used to identify novel disease-causing variants in the Korean population, highlighting the value of high-quality ethnic variation databases …


Transcriptomics Of Learning, Pablo Iturralde Jul 2018

Transcriptomics Of Learning, Pablo Iturralde

Theses

Learning is a basic and important component of behavior yet we have very little empirical information about the interaction between mechanisms of learning and evolution. In our work, we are testing hypotheses about the neurogenetic mechanisms through which animal learning abilities evolve. We are able to test this directly by using experimentally evolved populations of flies, which differ in learning ability. These populations were previously evolved within the lab by creating worlds with different patterns of change following theoretically predicted effects on which enhanced learning will evolve. How has evolution acted to modulate genes and gene expression in the brain …


Computational Analysis Of Papionini Evolution Using Alu Insertions, Vallmer Edward Jordan Ii Jun 2018

Computational Analysis Of Papionini Evolution Using Alu Insertions, Vallmer Edward Jordan Ii

LSU Doctoral Dissertations

Alu elements are primate specific retrotransposons that have remained active throughout the course of primate evolution. As a result of this sustained mobilization. Alu elements are present in greater copy number in primate genomes than any other transposable element. An average of over one million Alu elements has been identified in every sequenced haplorrhine genome to date. These characteristics qualify Alu elements as ideal characters for studying evolutionary relationship among primates.

The increasing availability of whole genome sequencing data presents novel challenges and opportunities for comparative genomic analyses. Genomic data is now publicly available for most primate species. Such an …


Systematics And Diversification Of The Pantropical Avian Order Coraciiformes, Jenna Merle Mccullough Jun 2018

Systematics And Diversification Of The Pantropical Avian Order Coraciiformes, Jenna Merle Mccullough

Biology ETDs

How and why species diversify is a central theme of evolutionary biology. Species-rich, morphologically diverse, pantropical clades provide rare opportunities to explore questions about drivers of diversification in the tropics. Here, we present the first complete species tree of Coraciiformes (6 families, ~177 species of kingfishers, motmots, bee-eaters, and allies), produced with thousands of ultraconserved elements. We recovered a well-supported tree which shows that there are two clades within Coraciiformes: 1) bee-eaters sister to rollers + ground- rollers and 2) todies sister to motmots + kingfishers. We estimated the biogeographical history of the group, explored bill shape evolution with a …


Polygenic Scores For Metabolic Traits And Related Drug Prescriptions In The Michigan Genomics Initiative, Samuel K. Handelman, Xiaomeng Du, Yanhua H. Chen, Elizabeth K. Speliotes Jun 2018

Polygenic Scores For Metabolic Traits And Related Drug Prescriptions In The Michigan Genomics Initiative, Samuel K. Handelman, Xiaomeng Du, Yanhua H. Chen, Elizabeth K. Speliotes

Biology and Medicine Through Mathematics Conference

No abstract provided.


Analysis Of Chromatin Interactions Of Beaf-Associated Promoters Using 4c, Shraddha Shrestha May 2018

Analysis Of Chromatin Interactions Of Beaf-Associated Promoters Using 4c, Shraddha Shrestha

LSU Doctoral Dissertations

A high degree of chromosome compaction is needed to fit nearly 2 meters of DNA inside a human nucleus of around 10 µm diameter. Correct chromatin folding is crucial to facilitate important nuclear functions such as transcription, DNA replication and DNA repair. Nuclei contain a variety of proteins, many of which help regulate chromatin structure and function. The mechanisms by which these proteins work are diverse and complicated. Here, we study the chromatin interactions of Boundary Element Associated Factor (BEAF) associated sites to gain insight into eukaryotic genome organization. We used circular chromosome conformation capture (4C) technology to detect genome-wide …


Modeling And Analyzing An Optogenetic System For Photoactivatable Protein Dissociation, Anvin Thomas, James Schaff May 2018

Modeling And Analyzing An Optogenetic System For Photoactivatable Protein Dissociation, Anvin Thomas, James Schaff

Honors Scholar Theses

Computational modeling of cell-cell interactions can grant clues and can answer questions about an experiment, especially for observations about binding interactions and kinetics. This approach was used to investigate an interaction between a light-oxygen-voltage (LOV) domain and an engineered protein called Zdark (Zdk). The LOV domain is membrane-bound while Zdk is cytosolic. The LOV domain and Zdk bind strongly in dark (Kd 26.2 nM), and weakly upon exposure to blue light (Kd > 4 μM). Total internal reflection fluorescence (TIRF) images are acquired of Zdk, the fluorescent species bound to a mCherry tag, and the loss of fluorescence is …


Isolation, Sequencing, And Characterization Of Four Transmissible Antibiotic Resistance Plasmids Captured From Bacteria In Stream Sediments, Curtis J. Kapsak May 2018

Isolation, Sequencing, And Characterization Of Four Transmissible Antibiotic Resistance Plasmids Captured From Bacteria In Stream Sediments, Curtis J. Kapsak

Masters Theses, 2010-2019

Self-transmissible plasmids are key vectors in the transfer of resistance, catabolic, and other genes among bacteria native to environments such as streams and wetlands. The evolution of antibiotic resistance in particular is known to be powerfully affected by conjugative plasmid transfer due to the ease in which some plasmids can be horizontally transferred into a broad range of host bacteria and their ability to exchange mobile genetic elements that often contain antibiotic resistance genes.

In this study, we captured tetracycline resistance plasmids from stream sediments impacted by agricultural runoff. We selected for resistance plasmids using tetracycline, an antibiotic commonly used …


Evolution Of Voltage-Gated Ion Channels, Kevin Gregory Bennett, Kevin Bennett May 2018

Evolution Of Voltage-Gated Ion Channels, Kevin Gregory Bennett, Kevin Bennett

Master of Science in Integrative Biology Theses

Voltage-gated Ion Channels (VICs) form a superfamily of energy-independent membrane transporters that facilitate the transfer of charged sodium, calcium, and potassium ions across the cell membrane (Hodgkin & Huxley 1952). The channels contain a selective ion-conducting pore along with several other structural and gating features that come together to form a functional hetero- or homotetramer. A comprehensive phylogenetic study of all available proteins aimed at finding unknown distribution and illuminating evolutionary paths would be immensely useful in understanding relationships of structure, function, and organismal distribution. This phylogenetic analysis of VICs will be immensely useful in characterizing functional and structural distribution, …


Functional Studies Of The E. Coli Proc And A Putative Ortholog Mrub_1345, Maureen Azar, Dr. Lori Scott May 2018

Functional Studies Of The E. Coli Proc And A Putative Ortholog Mrub_1345, Maureen Azar, Dr. Lori Scott

Meiothermus ruber Genome Analysis Project

This project is part of the Meiothermus ruber genome analysis project, which uses the bioinformatics tools associated with the Guiding Education through Novel Investigation –Annotation Collaboration Toolkit (GENI-ACT) to predict gene function. We investigated the biological function of Escherichia coli and Meiothermus ruber proC genes using the complementation assay. In this research project, mutants of varying severity to the functional state of the protein were developed. The results showed that two or more amino acid deletions reduced or eliminated ProC function. Amino acid substitutions, on the other hand, were not severe enough to impact ProC function. Double and triple mutants …


Determination Of Adamts13 Susceptibility In Type Iia Von Willebrand Disease, Monica Buselli May 2018

Determination Of Adamts13 Susceptibility In Type Iia Von Willebrand Disease, Monica Buselli

Dissertations, Masters Theses, Capstones, and Culminating Projects

von Willebrand Disease (vWD) is a bleeding disorder caused by a deficiency in von Willebrand Factor (vWF), a large glycoprotein that assists in coagulation. Specifically, large vWF multimers in the blood stream are key components in starting the coagulation cascade. vWF is cleaved by the metalloprotease ADAMTS13, regulating the multimers size, which hinders vWF’s ability to function properly. The three main types of vWD —Type I, II, and III— are not well defined, and as a result are all similarly treated with plasma-derived vWF replacement therapy. Plasma-derived vWF is a treatment that does not cure the problem but relieves the …


Changes In The Microbial Community Of Lubomirskia Baicalensis Affected By Red Sponge Disease, Colin Rorex May 2018

Changes In The Microbial Community Of Lubomirskia Baicalensis Affected By Red Sponge Disease, Colin Rorex

Electronic Theses and Dissertations

Lake Baikal is the oldest known lake and a unique ecosystem, home to several species of fresh water sponge. A disease outbreak affecting the dominant species, Lubormirskia baialensis, was recently reported. The cause of the disease has not been determined but one of the current hypothesis is that the increase in methane concentration is correlated to the disease outbreak. This pilot study characterized the microbiomes of sick and healthy sponges through the use of 16S rRNA sequencing. Sick sponge microbiomes shared a conserved group of taxa while the healthy sponge microbiomes had greater diversity. Indicator species analysis identified two significant …


Unravelling The Layers Of Cell Wall Synthesis And Function In Rice, Ritu Mihani May 2018

Unravelling The Layers Of Cell Wall Synthesis And Function In Rice, Ritu Mihani

Graduate Theses and Dissertations

The plant cell wall is of critical importance to plant growth and survival, functioning in maintaining structural integrity, supporting cell expansion, and acting as the first line of defense in response to biotic and abiotic stresses. The major components of the cell wall are cellulose, hemicelluloses, lignin, and pectin. Recent focus on the transcriptional machinery regulating cell wall biosynthesis in plants has revealed many key transcription factors responsible for orchestrating cell wall deposition. However, many of these TFs act redundantly and work coherently with a suite of TFs to activate the cell wall biosynthetic machinery. Heterologous expression of TFs is …


Region Based Gene Expression Via Reanalysis Of Publicly Available Microarray Data Sets., Ernur Saka May 2018

Region Based Gene Expression Via Reanalysis Of Publicly Available Microarray Data Sets., Ernur Saka

Electronic Theses and Dissertations

A DNA microarray is a high-throughput technology used to identify relative gene expression. One of the most widely used platforms is the Affymetrix® GeneChip® technology which detects gene expression levels based on probe sets composed of a set of twenty-five nucleotide probes designed to hybridize with specific gene targets. Given a particular Affymetrix® GeneChip® platform, the design of the probes is fixed. However, the method of analysis is dynamic in nature due to the ability to annotate and group probes into uniquely defined groupings. This is particularly important since publicly available repositories of microarray datasets, such as ArrayExpress and NCBI’s …


Phylogeny And Evolutionary Genomics Of Non-Photosynthetic Diatoms, Anastasiia Onyshchenko May 2018

Phylogeny And Evolutionary Genomics Of Non-Photosynthetic Diatoms, Anastasiia Onyshchenko

Graduate Theses and Dissertations

Diatoms are prolific photosynthesizers responsible for some 20% of global primary production. In real terms, the oxygen in one of every five breaths traces back to photosynthesis by marine diatoms. Among the tens of thousands of diatom species, a small handful of colorless diatom species in the genus Nitzschia have lost photosynthesis altogether and rely exclusively on extracellular organic carbon for growth. I used DNA sequence data to reconstruct the phylogeny of this group, and found that nonphotosynthetic diatoms are monophyletic, indicating that photosynthesis was lost just one time over the course of some 200 million years of diatom evolution. …