Arbeitsgruppe Hadrys

Forschungsgebiete

Die Forschungsaktivitäten kombinieren ökologische, evolutionsbiologische, molekulargenetische und bioinformatische Ansätze (inkl. CAOS-Barcoding, Transkriptomanalysen, Genexpressionsstudien, Genomanalysen), der modernen, interdisziplinären Biologie, um Kausalzusammenhänge in der Ökologie besser erklären zu können. Aktuelle Arbeitsthemen an Modellsystemen der Insekten sind: Artbildung, Verlust an Biodiversität, Anpassungsprozesse, Evolution von großen Bauplanveränderungen. Langzeitprojekte beschäftigen sich mit der Artenschutzgenetik, vergleichenden phylogenomischen und entwicklungsgenetischen Studien innerhalb der geflügelten Insekten (Pterygota) und den Auswirkungen des Klimawandels auf Artbildung und Anpassung.

Artenschutzgenetik:
Die Forschungsschwerpunkte im Rahmen der Artenschutzgenetik umfassen Studien zur Populationsgenetik, Phylogeographie und traditionelle Ökologie und Modellsysteme innerhalb der Libelle, sowie Artbildungsprozessen europäischer, afrikanischer und neotropischer Libellenarten. Hierbei kommen neueste molekulargenetische Techniken zur Anwendung inkl. Genom- und Transkriptomanalysen. Ein weiterer aktueller Schwerpunkt liegt auf der Untersuchung von klimatisch bedingten Anpassungsmechanismen im Rahmen des globalen Klimawandels anhand einzelner Modelsysteme innerhalb der Libellen.

Insektenphylogenie:
Generierung und verbesserte bioinformatische Analyse von molekulargenetischen Daten auf unterschiedlichen Ebenen (nukleäre Target-Gene, rRNA Gene, komplette mitochondriale Genome und Expressed Sequence Tags (ESTs)) zur Rekonstruktion der Verwandschaftsbeziehungen innerhalb der geflügelten Insekten (Pterygota).

Entwicklungsgenetik:
Entwicklungsgenetische Forschungsarbeiten am Modellsystem Drosophila haben wichtige Erkenntnisse zur Bauplanevolution geflügelter Insekten geliefert. Weiterführende Studien an regulatorischen Genen in einem phylogenetisch basalen pterygoten Insekt sind deshalb dringend angezeigt. Im speziellen Fokus steht hierbei die Charakterisierung des Hox-Genkomplexes und die Struktur der Einzelgene in der Kleinlibelle Ischnura elegans. Mittels in situ Hybridisierung werden nachfolgend die zeitlichen und räumlichen Expressionsmuster der Libellen-Hox-Gene aufgelöst; Gen-Knock Down Studien helfen bei der Aufklärung der Hox-Genfunktionen im Rahmen der Determination der Segmentidentitäten.

Charakter-basiertes Barcoding:
Anwendung charakter-basierter Barcodes zur Identifizierung von Arten durch die Anwesenheit oder Abwesenheit von diskreten Nukleotid Substitutionen (Charakteren) innerhalb einer DNA Sequenz. Während traditionelle DNA-Barcoding-Verfahren distanz-basiert sind und somit das Festlegen von "Grenzwerten" erzwingen, beruht das von uns mitentwickelte charakterbasierende Barcoding-Verfahren auf diskreten einzelnen Merkmalen und Merkmalskombinationen und erlaubt somit eindeutige, widerspruchsfreie Zuordnungen (Identifikationen) auf verschiedenen taxonomischen Ebenen. Dieses Projekt wird in Zusammenarbeit mit der Yale University und dem Amerikanischen Museum of Natural History, New York durchgeführt.

Schlagworte

Insekten, Libellen, Biodiversität, DNA- Barcoding, Evolution von Bauplänen, Phylogenomik, Bioinformatik, Entwicklungsgenetik, Molekulare Ökologie, Artbildung, Artenschutzgenetik und -genomik.

Areas of research

Our research topics include population genetics, phylogeny, phylogeography and conservation genetics in dragonflies and damselflies in Europe and the tropics, mainly Southern Africa and the Neotropics. To answer questions concerning population dynamics, dispersal potential, fragmentation effects, genetic isolation and speciation processes, we employ different genetic markers like microsatellite systems and sequence markers. To investigate aspects of climate change we perform gene expression experiments to analyze the ability of adaptation by rising temperatures.

1. Employment of microsatellites

Integrating genetic aspects in conservation biology may provide useful information about the status of populations. Because of the increasing number of threatened ecosystems through humans, the natural habitats of animals and plants are more and more endangered and often fragmented and isolated. To gain insights into the ability of a population to adapt to changing environmental conditions we use microsatellites to analyze different population genetic parameters like genetic variability and heterozygosity rates.
For example, we developed a microsatellite system for Othetrum coerulescens, which is a red listed species in Germany, to analyze genetic consequences (short and long term) of human interferences at its breeding habitat (Hadrys et al 2007). In Trithemis arteriosa we analyse how water-dependent species like Odonata are able to survive in desert regions. T. arteriosa is also an excellent bioindicator species for evaluating the quality of the rare water resources in Namibia (Giere & Hadrys 2006 ; Giere & Hadrys in prep).

Another aspect of our research is the application of microsatellites in parentage analyses. Here we developed a microsatellite system for the two sister species Anax imperator and Anax parthenope, to investigate the sperm precedence mechanism of these two species and to compare their different mating systems (Hadrys et al 2007).

2. Population genetics and phylogeny by means of sequence markers

Long term experiences in population genetics in Odonata carried out that the mitochondrial marker NADH-dehydrogenase subunit 1 (ND1) is an appropriate marker to study population dynamics and structures in this group (Groenefeld et al 2006). Therefore, we used this marker in diverse studies in different groups of dragonflies and damselflies. One main topic of our research is the comparison of dispersal potential of Southern African dragonfly species like in the genera Trithemis, Orthetrum and Crocothemis to investigate the genetic consequences of different habitat specialization in Namibia, Kenya and Tansania. We also analyze evolutionary aspects of speciation processes. Thus, we perform phylogenic analysis for the genera Trithemis, Anax, Pseudagrion. In the genus Trithemis through the employment of genetic markers a new cryptic species was found. For the phylogenic analysis we also use additional markers like 16S rDNA, Cytochromoxidase I (COI), Elongationfactor 1? (EF1) and the Internal Spacer region I and II (ITS I and II).

3. Gene expression studies in modern ecology

The ability to adapt to different environmental conditions is highly important for any kind of organisms especially in times of global warming and anthropogenic impacts of humans in their natural habitats. The integration of physiology in biodiversity research provides new insights into the potential of adaptation of organisms in a changing environment.
Therefore we described the Hsp70 protein for dragonflies, which belongs to the big group of chaperons and is one of the first genes expressed in a stressed organism. Hsp70 is a powerful biomarker for the early detection of stressful situations. Stress can be induced, for example, through a temperature shift at a given habitat or anthropogenic impacts like chemicals. The inclusion of Hsp70 as a biomarker in conservation projects may provide an early-warning measurement for environmental changes and pollution and we have a sensitive genetic tool to measure the water quality of the larval habitat and to evaluate the environmental conditions for the adult stage. We also could examine the potential of our domestic species to adapt by processes of global warming and compare to invasive tropical species, like Crocothemis erythreae, which is originally distributed through Africa and southern Europe and already able to preserve stable populations in the middle of Germany.

4. Character-based DNA barcoding

DNA barcoding has recently become very popular as a rapid and general method for the identification of organisms. Researchers are yet exploring suitable procedures that make DNA barcoding simple and reliable. Currently, distance approaches and tree building methods have been used to define species boundaries and discover cryptic species. These approaches highlight a central question: How can a species be defined? Obviously, a universal threshold of genetic distance values to distinguish taxonomic groups cannot be determined. A new promising alternative for DNA barcoding is the character-based approach. Here species are delimited through the presence or absence of discrete characters within a DNA sequence. Our data suggest that "character-based" DNA barcoding delivers an identification system that achieves (i) the assignment of odonate specimens to taxonomic groups and (ii) the discovery of conservation units rapidly and accurately. We show that character based DNA barcoding is a powerful alternative and harbors several advantages compared to phenetic approaches currently being used.
Odonates are excellent bioindicators for a variety of ecosystems due to substantial differences in habitat specificity and their complex life cycles. A reliable identification system for this insect group is therefore valuable for conservation management.

Keywords

Insects, Odonates, Biodiversity, DNA Barcoding, Evolution of Bauplans, Phylogenomics, Bioinformatics, Developmental Genetics, Molecular Ecology, Speciation, Conservation Genetics and Genomics.

Forschungsprojekte

Projektliste der Forschungseinrichtung
http://www.tiho-hannover.de/index.php?id=425&auto=28&sn=Hadrys

Kontakt

Ansprechpartner/-in

Forschungseinrichtung

Stiftung Tierärztliche Hochschule Hannover
Institut für Tierökologie und Zellbiologie
Arbeitsgruppe Hadrys
Hausanschrift:
Bünteweg 17 d
30559 Hannover
Telefon:
0511/953-8882
Telefax:
0511/953-8584
Stand: 17.02.2017
Dieses Forschungsprofil kann nicht online aktualisiert werden. Bitte lesen Sie dazu den Hinweis unter Datenpflege.