DOCSLIB.ORG

Open Kutz Thesis Final.Pdf

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Open Kutz Thesis Final.Pdf THE PENNSYLVANIA STATE UNIVERSITY SCHREYER HONORS COLLEGE DEPARTMENT OF BIOLOGY INVESTIGATING THE LARVAL COMPETITIVE ABILITIES OF DIFFERENT CHROMOSOMAL INVERSION PATTERNS WITHIN DROSOPHILA PSEUDOOBSCURA DAVID KUTZ SPRING 2018 A thesis submitted in partial fulfillment of the requirements for baccalaureate degrees in Biology and Spanish, with honors in Biology Reviewed and approved* by the following: Stephen Schaeffer Professor of Biology Thesis Supervisor Michael Axtell Professor of Biology Honors Adviser * Signatures are on file in the Schreyer Honors College. i ABSTRACT Within the fruit fly species D. pseudoobscura, the third chromosome has a wealth of genetic inversion mutations. These inversions vary in frequency among populations forming geographic clines or gradients under what appears to be strong natural selection. Models of selection – migration balance have suggested that the larval stage of development may be targeted by selection, however, the abiotic or biotic forces behind this selection remain unclear. To test for the influence of temperature and limited resources on selection, we performed larval competition experiments between wild type inversion strains and a standard mutant tester strain to test for differences among six different inversion lines. Our results indicate that when competition is less intense, temperature makes no difference in the ability of different inversion strains to compete. However, when competition is increased, a statistically significant difference in larval competitive success exists among flies carrying different inversions (p < 0.05). This suggests the selective forces driving the polymorphism likely exist when resources are limited. ii TABLE OF CONTENTS LIST OF FIGURES ..................................................................................................... iii LIST OF TABLES ....................................................................................................... iv ACKNOWLEDGEMENTS ......................................................................................... v Chapter 1 Introduction ................................................................................................. 1 Chapter 2 Methodology ............................................................................................... 4 Drosophila Strains. .......................................................................................................... 4 Experimental Design. ....................................................................................................... 5 Statistical Analysis. .......................................................................................................... 7 Chapter 3 Results ......................................................................................................... 9 Analysis of Outliers.......................................................................................................... 9 Temperature-based Analysis ............................................................................................ 9 Competition-based Analysis ............................................................................................ 11 Chapter 4 Discussion ................................................................................................... 13 Major Findings ................................................................................................................. 13 Broader Connections to Scientific Literature ................................................................... 14 Limitations and Opportunities for Further Investigation ................................................. 15 Appendix A DROSOPHILA STRAINS AND COLLECTING LOCALITIES .......... 17 BIBLIOGRAPHY ........................................................................................................ 18 iii LIST OF FIGURES Figure 1. Panel A: Map of D. pseudoobscura Inversion Frequencies along Geographic Clines throughout Southwest United States Panel B: The phylogeny of chromosome arrangements inferred from cytogenetic and molecular data. Circled arrangements indicate those studied in this experiment. (Fuller 2016). Republished with permission from Genetics Society of America. ........................................................................................................................... 3 Figure 2. Photograph of egg-laying chamber as described, State College, PA, January 2018. 5 Figure 3. Photographs of competition setup as described, State College, PA, May 2017. ...... 6 Figure 4. Mean % Wild-type out of Total Flies Survived (+/- SE of mean) by Inversion and Temperature. (18 and 24OC, respectively) May 2017. AR -– Arrowhead (n = 6, 5 ); CH - Chiricuahua; (n = 9, 9) CU - Cuernevaca; (n = 7, 9) PP - Pike's Peak; (n = 9, 9) ST -– Standard (n = 9, 9); TL - Tree Line (n = 9, 9). ................................................................. 11 Figure 5. Mean % Wild-type out of Total Flies Survived (+/- SE of the mean) by Inversion and Intensity of Competition. May 2017. AR -– Arrowhead (n = 6, 9); CH -– Chiricuahua (n= 9, 9); CU -– Cuernevaca (n= 9, 9); PP - Pike's Peak (n= 9, 9); ST -– Standard (n= 9, 9); TL - Tree Line (n= 9, 9). .......................................................................................................... 13 iv LIST OF TABLES Table 1. ANOVA Table at 18 Degrees Celsius with 15/15 Flies ............................................ 9 Table 2. ANOVA Table at 24 Degrees Celsius with 15/15 Flies ............................................ 10 Table 3. ANOVA Table Comparing High and Low Temperature Trials at Low Levels of Competition. ..................................................................................................................... 10 Table 4. ANOVA Table at 24 Degrees Celsius with 20/20 Flies ............................................ 11 Table 5. ANOVA Table at 24 Degrees Celsius Comparing Low and High Competition Trials. 12 v ACKNOWLEDGEMENTS First and foremost, I would like to thank Dr. Schaeffer for his consistent support and guidance throughout this process. In addition, I want to thank Haley Randolph for being there to help me through the initial steps of building my thesis. I would also like to acknowledge data support from the NIH grant NIH_ROI_GM098478. Outside the lab, my sincerest thanks to Dr. Axtell for reading my thesis and to the Schreyer Honors College for affording me so many opportunities throughout four years here in Happy Valley. I would be remiss if I did not also extend my gratitude to my parents, and to my closest friends for sticking with me the whole time. 1 Chapter 1 Introduction Chromosomal inversions are mutations that alter the order of genes in the genome. The mutations occur when two double stranded breaks are introduced along a chromosome and the central part of the chromosome is rejoined in reverse order to create a new gene arrangement. Chromosomal inversion polymorphisms are quite common in Drosophila (Sperlich and Pfriem, 1982), but the mechanisms responsible for the origin and maintenance of these chromosomal polymorphisms is not clear. More than 30 chromosomal inversions exist on the third chromosome of the fruit fly species Drosophila pseudoobscura (Dobzhansky and Sturtevant, 1938). These chromosomal inversions are thought to be selected in different environments based on circumstantial evidence.. Six of these inversions are widely distributed and reach high frequencies in the Southwest United States (Powell, 1992). Throughout the Southwest, each chromosomal inversion exists at population frequencies that vary along strict geographic clines, yet these frequencies have remained stable for nearly eight decades, despite consistent seasonal fluctuations (Figure 1) (Dobzhansky 1948, Anderson et al. 1991, Schaeffer 2008). Recombination is reduced in inversion heterozygotes because single cross overs generate non-viable gametes (Sturtevant and Beadle, 1936). As a consequence, each gene rearrangement has unique gene combinations that appear to be the targets of selection (Fuller et al. 2016, 2018), The maintenance of different gene arrangement frequencies at any one location suggests that the species is subjected to strong biotic and/or abiotic environmental pressure. In other words, in different areas within the 2 heterogeneous environment, each inversion must offer some form of selective advantage (Dobzhansky 1948). A model of selection – migration balance analyzed the nature of the stable coexistence of five specific inversions across various geographic niches: Standard (ST), Arrowhead (AR), Pikes Peak (PP), Tree Line (TL), Cuernavaca (CU), and Chiricahua (CH) (Schaeffer 2008). This model, which analyzed temperature and humidity, among other factors, used the logic of Levins and MacArthur (1966) to show that D. pseudoobscura experiences its environment in a coarse grain manner, in that a given organism spends the entire selective portion of its life within one specific niche of the varied environment. These niches also exist along rather strict geographic clines (Figure 1). Specifically for D. pseudoobscura, this selective phase is likely to be the larval stage of development because the larvae are incapable of migrating. In contrast, adults experience a fine-grained environment because they may easily traverse the heterogeneous niches. Therefore, all abiotic and biotic factors, such as temperature, rainfall, humidity, and even the presence of other toxin-secreting organisms are likely to exert their selective pressure
Load more

Recommended publications
  • The Elaborate Postural Display of Courting Drosophila Persimilis Flies Produces Substrate-Borne Vibratory Signals
    J Insect Behav DOI 10.1007/s10905-016-9579-8 The Elaborate Postural Display of Courting Drosophila persimilis Flies Produces Substrate-Borne Vibratory Signals Mónica Vega Hernández1 & Caroline Cecile Gabrielle Fabre1 Revised: 9 August 2016 /Accepted: 15 August 2016 # The Author(s) 2016. This article is published with open access at Springerlink.com Abstract Sexual selection has led to the evolution of extraordinary and elaborate male courtship behaviors across taxa, including mammals and birds, as well as some species of flies. Drosophila persimilis flies perform complex courtship behaviors found in most Drosophila species, which consist of visual, air-borne, gustatory and olfactory cues. In addition, Drosophila persimilis courting males also perform an elaborate postural display that is not found in most other Drosophila species. This postural display includes an upwards contortion of their abdomen, specialized movements of the head and forelegs, raising both wings into a Bwing-posture^ and, most remarkably, the males proffer the female a regurgitat- ed droplet. Here, we use high-resolution imaging, laser vibrometry and air-borne acoustic recordings to analyse this postural display to ask which signals may promote copulation. Surprisingly, we find that no air-borne signals are generated during the display. We show, however, that the abdomen tremulates to generate substrate-borne vibratory signals, which correlate with the female’s immobility before she feeds onto the droplet and accepts copulation. Keywords Biotremology.drosophila.persimilis.pseudoobscura.courtship.behavior. abdomen.tremulation.substrate-bornevibrations.femalestationary.quivering.feeding. copulation Electronic supplementary material The online version of this article (doi:10.1007/s10905-016-9579-8) contains supplementary material, which is available to authorized users.
    [Show full text]
  • Genetics of a Difference in Cuticular Hydrocarbons Between Drosophila Pseudoobscura and D
    Genet. Res., Camb. (1996), 68, pp. 117-123 With 3 text-figures Copyright © 1996 Cambridge University Press 117 Genetics of a difference in cuticular hydrocarbons between Drosophila pseudoobscura and D. persimilis MOHAMED A. F. NOOR* AND JERRY A. COYNE Department of Ecology and Evolution, University of Chicago, Chicago, 1101 E. 57th Street, IL 60637, USA Summary We identify a fixed species difference in the relative Oyama, 1995). Indeed, in almost every insect species concentrations of the cuticular hydrocarbons 2-methyl studied, some cuticular hydrocarbons have been found hexacosane and 5,9-pentacosadiene in Drosophila to play a pheromonal role (Cobb & Ferveur, 1996). pseudoobscura and D. persimilis, and determine its Because these compounds are easily extracted and genetic basis. In backcross males, this difference is due quantified by gas chromatography, they are ideal for to genes on both the X and second chromosomes, genetic studies of reproductive isolation. Three prev- while the other two major chromosomes have no ious studies have found that hydrocarbon differences effect. In backcross females, only the second chromo- between closely related species were probably caused some has a significant effect on hydrocarbon pheno- by only one or a few loci (Grula & Taylor, 1979; type, but dominant genes on the X chromosome could Roelofs et al., 1987; Coyne et al., 1994). also be involved. These results differ in two respects Here we identify a difference in the predominant from previous studies of Drosophila cuticular hydro- cuticular hydrocarbons of the well-known sibling carbons: strong epistasis is observed between the species Drosophila pseudoobscura and D. persimilis, chromosomes that produce the hydrocarbon analyze its genetic basis, and evaluate its potential difference in males, and the difference is apparently effects on reproductive isolation.
    [Show full text]
  • THEODOSIUS DOBZHANSKY January 25, 1900-December 18, 1975
    NATIONAL ACADEMY OF SCIENCES T H E O D O S I U S D O B ZHANSKY 1900—1975 A Biographical Memoir by F R A N C I S C O J . A Y A L A Any opinions expressed in this memoir are those of the author(s) and do not necessarily reflect the views of the National Academy of Sciences. Biographical Memoir COPYRIGHT 1985 NATIONAL ACADEMY OF SCIENCES WASHINGTON D.C. THEODOSIUS DOBZHANSKY January 25, 1900-December 18, 1975 BY FRANCISCO J. AYALA HEODOSIUS DOBZHANSKY was born on January 25, 1900 Tin Nemirov, a small town 200 kilometers southeast of Kiev in the Ukraine. He was the only child of Sophia Voinarsky and Grigory Dobrzhansky (precise transliteration of the Russian family name includes the letter "r"), a teacher of high school mathematics. In 1910 the family moved to the outskirts of Kiev, where Dobzhansky lived through the tumultuous years of World War I and the Bolshevik revolu- tion. These were years when the family was at times beset by various privations, including hunger. In his unpublished autobiographical Reminiscences for the Oral History Project of Columbia University, Dobzhansky states that his decision to become a biologist was made around 1912. Through his early high school (Gymnasium) years, Dobzhansky became an avid butterfly collector. A schoolteacher gave him access to a microscope that Dob- zhansky used, particularly during the long winter months. In the winter of 1915—1916, he met Victor Luchnik, a twenty- five-year-old college dropout, who was a dedicated entomol- ogist specializing in Coccinellidae beetles.
    [Show full text]
  • The Evolution of Prezygotic Reproductive Isolation in The
    Louisiana State University LSU Digital Commons LSU Doctoral Dissertations Graduate School 2005 The evolution of prezygotic reproductive isolation in the Drosophila pseudoobscura subgroup Sheri Dixon Schully Louisiana State University and Agricultural and Mechanical College, [email protected] Follow this and additional works at: https://digitalcommons.lsu.edu/gradschool_dissertations Recommended Citation Schully, Sheri Dixon, "The ve olution of prezygotic reproductive isolation in the Drosophila pseudoobscura subgroup" (2005). LSU Doctoral Dissertations. 1001. https://digitalcommons.lsu.edu/gradschool_dissertations/1001 This Dissertation is brought to you for free and open access by the Graduate School at LSU Digital Commons. It has been accepted for inclusion in LSU Doctoral Dissertations by an authorized graduate school editor of LSU Digital Commons. For more information, please [email protected]. THE EVOLUTION OF PREZYGOTIC REPRODUCTIVE ISOLATION IN THE DROSOPHILA PSEUDOOBSCURA SUBGROUP A Dissertation Submitted to the Graduate Faculty of the Louisiana State University and Agricultural and Mechanical College in partial fulfillment of the requirements for the degree of Doctor of Philosophy in The Department of Biological Sciences by Sheri Dixon Schully B.S., Louisiana State University, 2001 August 2005 DEDICATION I dedicate this dissertation to my parents, Lydia and Dale Dixon. My dad taught me the values of first-rate hard work. My mother has always made me feel that I could accomplish anything I put my mind and heart into. It has been her belief in me that has gotten me this far. ii ACKNOWLEDGEMENTS I would like to recognize and thank the people who made all of this work possible. First and foremost, I would like to express extreme gratitude to Mike Hellberg for his support and guidance.
    [Show full text]
  • In Nature, Not a Single Interspecific Hybridhas Ever Been Encountered
    792 GENETICS: T. DOBZHANSK Y PROC. N. A. S. EXPERIMENTS ON SEXUAL ISOLATION IN DROSOPHILA. X. REPRODUCTIVE ISOLA l ION BETWEEN DROSOPHILA PSE UDO- OBSCURA AND DROSOPHILA PERSIMILIS UNDER NATURAL AND UNDER LABORA TORY CONDITIONS By THEODOSIUS DOBZHANSKY COLUMBIA UNIVERSITY, NEW YORK Communicated October 25, 1951 The Problem.-The species Drosophila pseudoobscura and Drosophila persimilis are reproductively isolated. The isolation is the outcome of cumulative action of several isolating mechanisms, none of which is by itself fully effective. The distribution regions of these species are different, but they overlap broadly. Within the zone of the overlap, D. pseudo- obscura is relatively more common in warmer and drier habitats than D. persimilis, but they occur together in many localities. Sexual isolation can be demonstrated, in laboratory experiments, by placing females of both species with males of one of them. Homogamic matings (within the species) are usually more frequent than heterogamic ones (between species).1-4 Sexual isolation is also found when females and males of both species are present together in the same container.5 The intensity of the isolation is modified by environmental2' 4, 6 as well as by genetic variables,5 but in no experiment has a complete isolation been found. The inter- specific matings result, under laboratory conditions, in production of hybrids which appear to be fully as vigorous as the parents. The F1 males are, however, sterile, and the offspring of the F1 hybrid females show a pronounced constitutional weakness. In nature, not a single interspecific hybrid has ever been encountered, although certainly hundreds, and possibly as many as two thousand, flies collected in localities where both species occur together have been subjected at various times to cytological or genetic analysis which would detect such hybrids.
    [Show full text]
  • Enriched G-Quadruplexes on the Drosophila Male X Chromosome
    bioRxiv preprint doi: https://doi.org/10.1101/656538; this version posted June 2, 2019. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under aCC-BY-NC-ND 4.0 International license. Enriched G-quadruplexes on the Drosophila Male X Chromosome Function as Insulators of Dosage Compensation Complex Authors: Sheng-Hu Qian, Lu Chen, Zhen-Xia Chen* Affiliations: Hubei Key Laboratory of Agricultural Bioinformatics, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070, PR China *Correspondence to: [email protected] Abstract: The evolution of sex chromosomes has resulted in half X chromosome dosage in males as females. Dosage compensation, or the two-fold upregulation in males, was thus evolved to balance the gene expression between sexes. However, the step-wise evolutionary trajectory of dosage compensation during Y chromosome degeneration is still unclear. Here, we show that the specific structured elements G-quadruplexes (G4s) are enriched on the X chromosome in Drosophila melanogaster. Meanwhile, on the X chromosome, the G4s are underrepresented on the H4K16 acetylated regions and the binding sites of dosage compensation complex male-specific lethal (MSL) complex. Peaks of G4 density and potential are observed at the flanking regions of MSL binding sites, suggesting G4s act as insulators to precisely up-regulate certain regions in males. Thus, G4s may be involved in the evolution of dosage compensation process through fine-tuning one-dose proto-X chromosome regions around MSL binding sites during the gradual Y chromosome degeneration.
    [Show full text]
  • Hybrid Sterility and Segregation Distortion in Drosophila Pseudoobscura and Drosophila Persimilis
    Hybrid Sterility and Segregation Distortion in Drosophila pseudoobscura and Drosophila persimilis by Shannon Rose McDermott University Program in Genetics and Genomics Duke University Date:_______________________ Approved: ___________________________ Mohamed Noor, Supervisor ___________________________ Beth Sullivan ___________________________ John Willis ___________________________ Amy Bejsovec Dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy in the University Program of Genetics and Genomics in the Graduate School of Duke University 2012 ABSTRACT Hybrid Sterility and Segregation Distortion in Drosophila Pseudoobscura and Drosophila Persimilis by Shannon Rose McDermott University Program in Genetics and Genomics Duke University Date:_______________________ Approved: ___________________________ Mohamed Noor, Supervisor ___________________________ Beth Sullivan ___________________________ John Willis ___________________________ Amy Bejsovec An abstract of a dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy in the University Program in Genetics and Genomics in the Graduate School of Duke University 2012 Copyright by Shannon McDermott 2012 Abstract Speciation has occurred countless times throughout history, and yet the genetic mechanisms that lead to speciation are still missing pieces. Here, we describe the genetics of two processes that can act alone or together to cause speciation: hybrid sterility and meiotic drive. We use the Drosophila pseudoobscura /D, persimilis species as a model system to study these processes. We expanded on a prior study and saw little variation in strength of previously known hybrid sterility alleles between distinct strains of D. persimilis and the Bogota subspecies of D. pseudoobscura . Introgression of an autosomal, noninverted hybrid sterility allele from the USA subspecies of D. pseudoobscura into D. persimilis demonstrated that the D.
    [Show full text]
  • Inversions Shape the Divergence of Drosophila Pseudoobscura and D
    bioRxiv preprint doi: https://doi.org/10.1101/842047; this version posted November 14, 2019. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under aCC-BY-NC 4.0 International license. Inversions shape the divergence of Drosophila pseudoobscura and D. persimilis on multiple timescales Katharine L Korunes1*, Carlos A Machado2, Mohamed AF Noor3 1. Department of Evolutionary Anthropology, Duke University, Durham, NC 27708 2. Department of Biology, University of Maryland, College Park, Maryland 20742 3. Biology Department, Duke University, Durham, NC 27708 * Corresponding author: [email protected] 1 bioRxiv preprint doi: https://doi.org/10.1101/842047; this version posted November 14, 2019. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under aCC-BY-NC 4.0 International license. 1 Abstract 2 By shaping meiotic recombination, chromosomal inversions can influence genetic exchange between 3 hybridizing species. Despite the recognized importance of inversions in evolutionary processes such as 4 divergence and speciation, teasing apart the effects of inversions over time remains challenging. Many recent 5 studies have examined gene exchange between hybridizing species and observed higher divergence associated 6 with inversion polymorphisms in hybrids. Studies have attributed such patterns either to interspecies gene 7 flow homogenizing collinear regions or to pre-speciation segregation of inversion polymorphisms in the 8 ancestral population.
    [Show full text]
  • Endogenous Viral Elements Are Widespread in Arthropod Genomes and Commonly Give Rise
    bioRxiv preprint doi: https://doi.org/10.1101/396382; this version posted August 20, 2018. The copyright holder for this preprint (which was not certified by peer review) is the author/funder. All rights reserved. No reuse allowed without permission. 1 1 Endogenous viral elements are widespread in arthropod genomes and commonly give rise 2 to piRNAs 3 4 Anneliek M. ter Horst*, Jared C. Nigg*†, and Bryce W. Falk 5 * These authors contributed equally to this work 6 † Corresponding author 7 8 Department of Plant Pathology, University of California Davis, 1 Shields Avenue, Davis, CA 9 95616 10 11 [email protected] 12 [email protected] 13 [email protected] 14 15 ABSTRACT 16 Arthropod genomes contain sequences derived from integrations of DNA and non- 17 retroviral RNA viruses. These sequences, known as endogenous viral elements (EVEs), have 18 been acquired over the course of evolution and have been proposed to serve as a record of past 19 viral infection. Recent evidence indicates that EVEs can function as templates for the biogenesis 20 of PIWI-interacting RNAs (piRNAs) in some mosquito species and cell lines, raising the 21 possibility that EVEs may function as a source of immunological memory in these organisms. 22 However, whether EVEs are capable of acting as templates for piRNA production in other 23 arthropod species is unknown. Here we used publically available genome assemblies and small bioRxiv preprint doi: https://doi.org/10.1101/396382; this version posted August 20, 2018. The copyright holder for this preprint (which was not certified by peer review) is the author/funder.
    [Show full text]
  • Phylogenomic Resources at the UCSC Genome Browser
    9 Phylogenomic Resources at the UCSC Genome Browser Kate Rosenbloom, James Taylor, Stephen Schaeffer, Jim Kent, David Haussler, and Webb Miller Summary The UC Santa Cruz Genome Browser provides a number of resources that can be used for phylogenomic studies, including (1) whole-genome sequence data from a number of vertebrate species, (2) pairwise alignments of the human genome sequence to a number of other vertebrate genome, (3) a simultaneous alignment of 17 vertebrate genomes (most of them incompletely sequenced) that covers all of the human sequence, (4) several independent sets of multiple alignments covering 1% of the human genome (ENCODE regions), (5) extensive sequence annotation for interpreting those sequences and alignments, and (6) sequence, alignments, and annotations from certain other species, including an alignment of nine insect genomes. We illustrate the use of these resources in the context of assigning rare genomic changes to the branch of the phylogenetic tree where they appear to have occurred, or of looking for evidence supporting a particular possible tree topology. Sample source code for performing such studies is available. Key Words: Evolutionary event; phylogenetic tree; interspersed repeat; chromosomal break. 1. Introduction Rare genomic changes (RGCs), such as retroposon integrations, indels (insertions/deletions) in protein-coding regions, and inversions, provide useful alternatives to the use of nucleotide and amino-acid substitutions for determining the evolutionary relationships among living organisms (1). If one knows where in the genome to look, the UCSC Genome Browser (2,3) and the associated database (4) make it easy to see evidence that an RGC occurred at a particular point in evolutionary history.
    [Show full text]
  • Adaptation, Ancestral Variation and Gene Flow in a 'Sky Island
    bioRxiv preprint doi: https://doi.org/10.1101/2020.05.14.096008; this version posted October 8, 2020. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under aCC-BY-NC-ND 4.0 International license. Adaptation, ancestral variation and gene flow in a ‘Sky Island’ Drosophila species Tom Hill1*, Robert L. Unckless1 1. 4055 Haworth Hall, The Department of Molecular Biosciences, University of Kansas, 1200 Sunnyside Avenue, Lawrence, KS 66045. * Corresponding author: Email: [email protected] Keywords: Drosophila innubila, local adaptation, phylogeography, inversions 1 bioRxiv preprint doi: https://doi.org/10.1101/2020.05.14.096008; this version posted October 8, 2020. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under aCC-BY-NC-ND 4.0 International license. 1 Abstract 2 Over time, populations of species can expand, contract, fragment and become isolated, creating 3 subpopulations that must adapt to local conditions. Understanding how species maintain variation after 4 divergence as well as adapt to these changes in the face of gene flow, is of great interest, especially as the 5 current climate crisis has caused range shifts and frequent migrations for many species. Here, we 6 characterize how a mycophageous fly species, Drosophila innubila, came to inhabit and adapt to its current 7 range which includes mountain forests in southwestern USA separated by large expanses of desert.
    [Show full text]
  • Divergent Sensory Investment Mirrors Potential Speciation Via Niche Partitioning Across Drosophila Ian W Keesey*, Veit Grabe, Markus Knaden†*, Bill S Hansson†*
    RESEARCH ARTICLE Divergent sensory investment mirrors potential speciation via niche partitioning across Drosophila Ian W Keesey*, Veit Grabe, Markus Knaden†*, Bill S Hansson†* Max Planck Institute for Chemical Ecology (MPICE), Department of Evolutionary Neuroethology, Jena, Germany Abstract The examination of phylogenetic and phenotypic characteristics of the nervous system, such as behavior and neuroanatomy, can be utilized as a means to assess speciation. Recent studies have proposed a fundamental tradeoff between two sensory organs, the eye and the antenna. However, the identification of ecological mechanisms for this observed tradeoff have not been firmly established. Our current study examines several monophyletic species within the obscura group, and asserts that despite their close relatedness and overlapping ecology, they deviate strongly in both visual and olfactory investment. We contend that both courtship and microhabitat preferences support the observed inverse variation in these sensory traits. Here, this variation in visual and olfactory investment seems to provide relaxed competition, a process by which similar species can use a shared environment differently and in ways that help them coexist. Moreover, that behavioral separation according to light gradients occurs first, and subsequently, courtship deviations arise. *For correspondence: [email protected] (IWK); [email protected] (MK); Introduction [email protected] (BSH) The genus Drosophila provides an incredible array of phenotypic, evolutionary and ecological diver- †These authors contributed sity (Jezovit et al., 2017; Keesey et al., 2019; Keesey IW et al., 2019; Markow, 2015; equally to this work Markow and O’Grady, 2007; O’Grady and DeSalle, 2018). Members of this genus, which provides roughly 1500 species including the model organism D.
    [Show full text]