Alternative model organisms: growing popularity, and the challenges

screenings facilitates adherence to these principles while reducing costs (1).Different branches of biological, clinical, and environmental research rely heavily on the availability of a suitable model organism, which can mimic the actual application platform, while allowing the work to progress at a reasonable speed.Research on certain pathogens (e.g.certain obligate intracellular parasites, including viruses) is often hampered due to the non-availability of a compatible model organism.On the other side, there are some organisms that match the criteria of being an acceptable model so well that they have become almost indispensable for research in specific domains.For instance, Escherichia coli has remained the handiest model for bacteriological research for decades, and one of the most popular platforms for expressing cloned genes.Saccharomyces cerevisiae has been widely exploited as a model yeast and as a platform for bioprocess intensification for industrial alcohol production.Candida albicans serves as a model for pathogenic yeasts.Mycobacterium smegmatis has helped the researchers develop useful insights into the genus Mycobacterium without necessitating the risk of handling M. tuberculosis.Pre-clinical research has depended heavily on pig, mouse, rat, and primate models.However, in the face of the serious ethical concerns raised over the use of higher animals in research labs, alternative strategies are being envisaged to reduce their sacrifice.In this background scenario, three lower organisms-Caenorhabditis elegans, Drosophila melanogaster, and zebrafish-have gained increasing popularity, particularly for preliminary in vivo studies.Though they are not new to biology labs, their use has gained wider popularity in the last two decades, and the availability of their transgenic strains has contributed notably towards extending their utility spectrum.While use of conventional model organisms still continues, the alternative models (nematode, fly, zebrafish) are gaining entry in more and more labs, new models are being proposed, and the regulatory agencies globally are trying to reduce the animal sacrifice in biological and pharmaceutical research."Organ on a chip" type of novel approaches are also expected to contribute towards reduced use of model animals in research.The field is slowly changing and evolving dynamically, and there is a need for researchers in the fields of biology, pharmacy, cosmetics, nutraceuticals, toxicology, and environmental sciences to keep themselves updated.With each passing year, the scientific community is witnessing a transformative shift toward alternative model organisms, driven by a combination of ethical mandates (such