 Illustration by Kai Yara By Servi Bulu A 1 millimeter worm helped scientists map an entire organism's nervous system for the first time. Many major leaps in biology, such as this one, owe their thanks to model organisms like C. elegans. Model organisms are non-human species studied to understand biological processes that often generalize to other species, such as humans. Model organisms are fundamental to biological research because they provide standardized platforms that allow scientists to build on shared findings and collaborate globally, accelerating discovery (Yang & Du, 2025). Many of these organisms share key characteristics: they reproduce and mature rapidly, are easily maintained in the lab, and have well-understood genetics that can be easily manipulated. They also share fundamental cellular and molecular mechanisms with humans and other species, making them powerful proxies when direct human studies are limited by ethical and practical constraints (Yang & Du, 2025).
Among the most celebrated model organisms in the history of biology is Caenorhabditis elegans (also known as C. elegans), a transparent nematode worm that revolutionized developmental biology. Introduced by Sydney Brenner in the 1960s, C. elegans offered something unprecedented: an organism small enough to be studied under a microscope, yet complex enough to serve as a model of multicellular life (Alberts et al., n.d.). The species exists only as males and hermaphrodites (the latter capable of self-fertilization), making it exceptionally easy to reproduce. Over time, scientists succeeded in mapping every one of its cells: all 959 somatic cells of the hermaphrodite and 1,031 of the male, including every single neuron, a first in the field (Riddle et al., 1997). This complete map has opened new frontiers for scientific exploration, and, since 2002, discoveries using C. elegans have won 4 Nobel Prizes (Smith, 2024). While C. elegans represents the possibilities that a simple organism can offer into the complexity of life, Drosophila melanogaster, the fruit fly, showcases the power of genetic complexity. It has been used in labs for over a century and is the foundation of modern genetics. Thomas Hunt Morgan’s “Fly Room” at Columbia University’s Schermerhorn Hall demonstrated that genes reside on chromosomes, foundational to modern genetics (Carlson, 2013). Later work on Drosophila identified Hox genes, which specify the structures that form in each body part during embryonic development and are conserved across nearly all animals, including humans (Loker, 2021). These breakthroughs cemented Drosophila as a core genetic tool; over the past century, six Nobel Prizes have been awarded to 10 scientists working with these flies (McKie, 2017). While worms and flies dominate the microscopic scene, Mus musculus (the house mouse) stands as the leading mammalian model in research. They’re especially indispensable in the biomedical field, as they share ~90% of their disease-associated genes with humans (Mayor, 2002). According to the European Animal Research Association, “mice are the most used animal for scientific purposes in the EU, making up more than half (52.5%) of the total number of animals used in research–5,459,433 animals in 2019. (European Animal Research Association, n.d.)” New genetic tools that let researchers add, remove, or switch off specific genes, and observe the consequences, have yielded insights into cancer, diabetes, Alzheimer’s disease, and many other conditions. The humble house mouse, central to these approaches, has been associated with 42 Nobel Prizes (Nobel Prizes in Physiology or Medicine, n.d.)! In the realm of vertebrate development, Danio rerio, the zebrafish, has emerged as an equally vital model. Although used since the 1960s, zebrafish gained prominence through George Streisinger’s work in the 1970s-80s, establishing a simpler vertebrate model than the house mouse for studying the nervous system (Tiny Fish, Big Splash: The Story of the Zebrafish, n.d.). Transparent zebrafish embryos provide a rare window into embryonic development, allowing researchers to link specific genes to tissue and organ development. Another boost in the 1990s, led by Christiane Nüsslein-Volhard and Wolfgang Driever, who were searching for interesting mutations in fish, further popularized the organism. Even though they share their only Nobel Prize with fruit flies, they have earned their spotlight for sure. At the end of the day, we owe much of our understanding of life’s most intricate processes to these small, but mighty creatures. From nematodes to zebrafish to many innumerable other organisms, each illuminates a new layer of the complexity of life on Earth. References Alberts, B., Johnson, A., & Lewis, J. (n.d.). Molecular Biology of the Cell - Caenorhabditis Elegans: Development from the Perspective of the Individual Cell (4th edition). Garland Science. Retrieved October 15, 2025, from https://www.ncbi.nlm.nih.gov/books/NBK26861/ Carlson, E. A. (2013). How fruit flies came to launch the chromosome theory of heredity. Mutation Research/Reviews in Mutation Research, 753(1), 1–6. https://doi.org/10.1016/j.mrrev.2013.03.001 Crowley, R. (2024, January 17). Research Organism Superheroes: Fruit Flies. National Institute of General Medical Sciences. https://nigms.nih.gov/biobeat/2024/01/research-organism-superheroes-fruit-flies European Animal Research Association. (n.d.). Mice and animal research. European Animal Research Association. Retrieved October 15, 2025, from https://www.eara.eu/mice-and-animal-research Loker, R. (2021, August 5). Flies with Four Wings? Investigating Genes that Pattern Animal Bodies. Zuckerman Institute. https://zuckermaninstitute.columbia.edu/flies-four-wings-investigating-genes-pattern-animal-bodies Mayor, S. (2002). Mouse genome shows many disease genes shared with humans. BMJ : British Medical Journal, 325(7376), 1319. National Library of Medicine. https://pmc.ncbi.nlm.nih.gov/articles/PMC1124795/ McKie, R. (2017, October 7). Six Nobel prizes – what’s the fascination with the fruit fly? The Guardian; Guardian News & Media Limited. https://www.theguardian.com/science/2017/oct/07/fruit-fly-fascination-nobel-prizes-genetics Nobel Prizes in Physiology or Medicine. (n.d.). Foundation for Biomedical Research. Retrieved October 15, 2025, from https://fbresearch.org/medical-advances/nobel-prizes Riddle, D., Blumenthal, T., & Meyer, B. (1997). C. elegans II - Section I, The Biological Model (2nd edition). Cold Spring Harbor Laboratory Press. https://www.ncbi.nlm.nih.gov/books/NBK20086/ Smith, J. (2024). Daily briefing: The “badass” worm behind 4 Nobel prize wins. Nature. https://doi.org/10.1038/d41586-024-03453-8 Tiny fish, big splash: the story of the zebrafish. (n.d.). Your Genome. Retrieved October 15, 2025, from https://www.yourgenome.org/theme/tiny-fish-big-splash-the-story-of-the-zebrafish/ Yang, M., & Du, Z. (2025). Reaffirming the value of model organisms in training scientific minds. Nature Cell Biology, 27. https://doi.org/10.1038/s41556-025-01754-2
0 Comments
Leave a Reply. |