In biomedical research, small model organisms such as the fruit fly Drosophila melanogaster are important pillars in the process of scientific discovery. I have been using Drosophila as my organism of choice and my essential discovery tool to study fundamental principles of the nervous system [LINK1, LINK2] for 26 years.
Together with my colleague Sanjai Patel, I have been actively engaging in science communication for 5 years now, aiming to raise public awareness of the importance of fly research with a strong focus on school activities. From this, we realised the enormous potential that Drosophila has beyond research also for biology teaching. It is a powerful modern teaching tool not only for classical Genetics but for many curriculum-relevant areas of biology, providing unique access to informative, inspiring and memorable classroom experiments. To capitalise on this opportunity, we now collaborate with teachers and schools on the droso4schools project (see 1st movie below), developing freely available sample lessons with adjunct materials (e.g. teacher notes, risk assessments, homework tasks, exercises, experiment instructions), and a dedicated website (Resource 1) providing many helpful online resources.
Why is Drosophila so important for biomedical research?
Naturally, students want to know why flies are used to learn biology. The explanation is made easy with our two “Small fly, big impact” movies (see the two movies below), which were tested in schools with great success. Furthermore, there is a dedicated tab on our droso4schools website which provides further background information (Resource 1b). In a nutshell, the films and website explain…
- …that it was serendipity which brought flies into genetic research a hundred years ago,
- …that it were the many practical advantages and cost-effectiveness of Drosophila which made it so popular for studying the function and biology behind genes, and
- …that it is the astonishingly high degree of evolutionary conservation from flies to humans that makes understanding of biology in flies so relevant for biomedical research even into human disease, having led to five Nobel prizes in Physiology and Medicine so far.
Why is Drosophila so useful in biology classes?
As will become clear from the sample lessons explained in the next section, there are two important advantages for using Drosophila in classrooms, in particular (1) the breadth and depth of conceptual understanding of biology in the fly, and (2) the fact that flies are uniquely suited for live experiments in schools.
- Conceptual understanding: A century of cutting edge research has turned Drosophila into the conceptually best understood animal model organism that we have to date. It has not only taught us about how genes are organised on chromosomes and the rules of inheritance, but also fundamental concepts of development, nervous system function, the immune system, our biological clock and jet lag, evolution and population genetics, the genetics of learning, principles of stem cells, and even mechanisms of disease including cancer and neurodegeneration (see Resource 2b “Why the fly?”). But how does this help in classrooms?
- The breadth of biology topics investigated in flies provides potential teaching materials for a wide range of curriculum-relevant biology specifications, ranging from classical genetics to gene technology, gene expression, enzymes, neurobiology and even evolution and behaviour.
- The sheer volume of knowledge in each of those areas provides a plethora of examples, experiments, anecdotes and facts that can be used to illustrate and make lessons more engaging and entertaining.
- The depth and detail of conceptual understanding in flies facilitates teaching, based on the simple rationale that teaching is the easier the better the contents are understood.
- Live experiments: It is straightforward, cheap and ethically unproblematic to use and breed flies in schools, and there are many simple experiments that can be performed (see our sample lessons in the next section). This brings living animals into classrooms which, combined with experiments that reflect relevant contemporary research, tends to leave long-lasting experiences. I frequently talk to people who were taught classical genetics with flies decades ago and still hold positive memories.
Examples of biology contents that can be taught with flies
There are many ways in which flies can be used as teaching tools in schools. Here we will give some examples for which resources are either provided online already or can be made available upon request.
(1) Life cycle
Teaching the life cycle in primary schools is often done using metamorphosis of tadpoles into frogs or of caterpillars into butterflies, but experiencing these examples in real time can only be done during a certain period of the year and takes many weeks. With flies this can be done in one day since all life forms are available at any time, and the whole life cycle can be experienced in real time during less than two weeks (see image below and Resource 2c).
(2) Principal functions of our organs
The physiological requirements for life are so fundamental that most of our organs have common evolutionary roots. An active and effective way to learn about our organs is therefore through exploring their commonalities with organs of other organisms. This strategy can capitalise on the vast knowledge that we have about the tissues and organs of Drosophila. To facilitate this, we provide a dedicated webpage describing the structures and fundamental functions of our organs in direct comparison to those of the fruit fly (Resource 1c).
(3) The genetics of alcohol metabolism
This lesson is fully developed, was tested with eighty Year 13 students (one high achievers class, two mixed ability classes, one support class), a PowerPoint file with adjoint materials is available online (Resource 1a, e, 3b) and a dedicated webpage is available to support revision and homework tasks (Resource 1e). It is an excellent synoptic, end-of-year lesson which establishes conceptual links between at least seven curriculum-relevant biology specifications. These include fermentation, the gene to protein concept, enzyme function, pharmacology and associative learning, genetic variation, and principles of evolution. Students dissect normal and alcohol dehydrogenase deficient fly maggots and use a colour reaction to assess the maggots’ ability to metabolise alcohol. They observe the effects of alcohol consumption on normal and mutant flies, and they compare different alleles of the Adh gene by translating their DNA code into RNA and protein. This lesson offers excellent opportunities to achieve differentiation and to discuss the social relevance of alcohol and alcohol abuse.
(4) Applying statistics to performance tests of young versus ageing flies
This lesson is also available as a resource online accompanied by 5 dedicated webpages (Resource 1a, d, 3a). It was tested on sixty Year 9 pupils. It uses a low-cost, easy to set-up experiment known as the “climbing test”: two groups of flies (one week old teenagers versus five week old seniors) are tapped down in two parallel vials and are given 15 seconds to climb back up, at which point a picture is taken. Students then determine how far the ten individual flies in each vial have climbed on a scale of 0 to 10, usually finding that the young flies show much better motor-performance. This is then used to draw graphs, understand the importance of sample numbers and learn to apply statistics. To illustrate relevance, concepts of ageing and neurodegeneration are introduced accompanied by activity sheets, and examples are provided on how the climbing assay is used during ageing and neurodegeneration research on flies.
(5) Classical genetics
This lesson is not yet available online, but will be sent out upon request. During this lesson, students learn about classical genetics and the practical uses of marker mutations as they are applied in contemporary research laboratories (including Punnett squares). For this, excellent low cost dissection microscopes can be used (see Resource 2c “Outreach Resources”), and we developed simple activities where student success in identifying markers is easy to monitor. Furthermore, the lesson provides an insight into the process of scientific discovery (how it was found that genes lie on chromosomes), and how this helps understanding biological phenomena in humans, such as male predisposition to colour blindness. Where transgenic flies are permitted on school grounds, modern genetic markers can also be used, in particular fly strains containing green fluorescent proteins. Using a simple hand-held fluorescent lamp with integrated camera (see Resource 2c “Outreach Resources”), gleaming organs can be observed live in these maggots.
(6) Fundamental principles of the nervous system
This lesson introduces to the wiring principles of the nervous system, action potentials, and the working of synapses, illustrated by shaking epileptic flies into seizure or paralysing flies through warming them to body temperature. Where transgenic flies are permitted on school grounds, the use of state-of-the-art opto- or thermo-genetics (using light or temperature to manipulate nerve cells and fly behaviours; see this TED talk).
Further ideas or requests?
Many more curriculum-relevant topics can be taught using Drosophila as a modern teaching tool, and we are curious to hear which ones would be of interest to you, and we will collaborate with you to implement such lessons. Feel free to contact us: Andreas.Prokop@manchester.ac.uk and Sanjai.Patel@manchester.ac.uk.
- The droso4schools website provides relevant information:
- an overview of the project and of available sample lessons;
- the “Why fly?” page explains the advantages of Drosophila in research;
- the “Organs” page compares tissues and organs of flies and humans with helpful overview images.
- the “L1-Climbing Assay” tab provides 5 pages of information supporting the motorskills experiment: (1) a description of the experiment, (2) background information on neurodegenerative diseases and ageing, (3) information of how flies are used to study these conditions, (4) a glossary of relevant terms, and (5) explanations of relevant statistics;
- the “L2-Alcohol” provides background information for the lesson on alcohol, covering fermentation, principles of enzymes, drug treatment of alcohol addiction, natural variation of alcohol tolerance and their genetic basis, the geographical distribution of variations and their evolutionary basis
- The “For the Public” area of the Manchester Fly Facility website
- the “Why the fly?” page complements the information on droso4schools through listing simple facts and over 80 lay articles about fly research;
- the “Teachers & Schools” page explains the rationale for our school work and lists the services we provide for schools to support fly lessons, as well as our past/future school events;
- the “Outreach Resources” page lists about 100 links to information and resources that can be useful for outreach work and teaching at school and university levels.
- The figshare.com resource site for download of sample lessons and adjoined resource materials
- zip file containing the L1-Climbing Test lesson
- zip file containing the L2-Alcohol lesson
- Manchester Fly Facility YouTube channel
- two educational “Small fly, big impact” movies describing the origins and importance of fly research (part 1 – “Why the fly?”) and how research in flies can help to understand disease and find potential treatments (part 2 – “Making research fly”)
- a film explaining the droso4school project through interviews with all involved