What is a model organism?
A model organism is a species that has been widely studied, usually because it is easy to breed in a laboratory setting, and has particular experimental advantages [1]. They typically are used by scientists in a laboratory to better understand biological processes. Model organisms include but are not limited to: mice, zebrafish, yeast, c. elegans, and fruit flies.
Why are model organisms useful for genetic research? [1]
- Many model organisms can breed in large numbers
- Some have a very short generation time (the time between being born and being able to reproduce), so several generations can be followed at once
- Mutants allow scientists to study certain characteristics or diseases. These are model organisms that have undergone a change or mutation in their DNA that may result in a change in a certain characteristic.
- Some model organisms have similar genes or similar-sized genomes to humans.
- Model organisms can be used to create highly detailed genetic maps
Commonly Used Model Organisms:
Mus musculus (Mouse) [3]
Mice are the foremost mammalian model for studying human disease. The mouse is small, and breeds very well. Their genes can be easily manipulated as well as the phenotype of the mutants are similar to humans and are clearly visible. Mice lack maculars (center of the eye), however, and are a debated candidate as a model organism for diseases with retinal degeneration. Saccharomyces cerevisiae (Yeast) [4]
Yeast is one of the simplest eukaryotic organisms, however, many essential cellular processes are similar in yeast and humans. They are very easy to manipulate, can cope with a wide range of environmental conditions, and can control cell division in similar ways to human cells. Yeast lack eyes; however, and would be quite difficult to study for retinal degeneration. |
Drosophila melanogaster (Fruit Fly) [2]
Drosophila are multicellular organisms that are cheap and very easy to work with. They have a short life cycle, small genome size, and reproduce in large amounts. Also, they very clearly display a phenotype similar to humans when the CLN3 gene is manipulated. For example, they display retinal degeneration, muscular dystrophy in wings, and increased cellular waste surrounding neuronal lysosomes when CLN3 is mutated. |
Which model organism should be used to study CLN3? [5]
Drosophila melanogaster show clear phenotypes that are similar to humans when CLN3 is mutated. This could be very useful to discover which type of mutation of CLN3 causes Batten Disease as well as what parts of the gene cause vision degeneration versus neurodegenerative degradation.
Conclusion
Model organisms are essential to studying biological processes of a gene. While CLN3 has been studied in most of the organisms listed above, Drosophila melanogaster have proven to show clear phenotypes when CLN3 is manipulated. They are also cheap,easy to breed, and have a short lifespan, meaning numerous tests could be conducted over a short period of time.
References:
[1] What are model organisms? (2017, March 03). Retrieved from https://www.yourgenome.org/facts/what-are-model-organisms
[2] Gsa. (n.d.). Retrieved from http://modencode.sciencemag.org/drosophila/introduction
[3]Why mouse genetics? (n.d.). Retrieved from https://www.jax.org/personalized-medicine/why-mouse-genetics
[4] Using yeast in biology. (2016, June 14). Retrieved from https://www.yourgenome.org/stories/using-yeast-in-biology
[5] I., R., Vivancos, V., & B., M. (2008, November 21). Interactions between the juvenile Batten disease gene, CLN3 , and the Notch and JNK signalling pathways. Retrieved from https://academic.oup.com/hmg/article/18/4/667/601791
Header: https://www.quantamagazine.org/biologys-search-for-new-model-organisms-20160726/
Figure 1: https://depositphotos.com/stock-photos/mouse-animal.html
Figure 2: http://www.reptilesupplyco.com/wholesale-fruit-flies/3005-fruit-flies-d-melanogaster-4-cups.html
Figure 3: https://www.britannica.com/science/yeast-fungus
Figure 4: https://academic.oup.com/hmg/article/18/4/667/601791
Figure 5: https://academic.oup.com/hmg/article/18/4/667/601791
[2] Gsa. (n.d.). Retrieved from http://modencode.sciencemag.org/drosophila/introduction
[3]Why mouse genetics? (n.d.). Retrieved from https://www.jax.org/personalized-medicine/why-mouse-genetics
[4] Using yeast in biology. (2016, June 14). Retrieved from https://www.yourgenome.org/stories/using-yeast-in-biology
[5] I., R., Vivancos, V., & B., M. (2008, November 21). Interactions between the juvenile Batten disease gene, CLN3 , and the Notch and JNK signalling pathways. Retrieved from https://academic.oup.com/hmg/article/18/4/667/601791
Header: https://www.quantamagazine.org/biologys-search-for-new-model-organisms-20160726/
Figure 1: https://depositphotos.com/stock-photos/mouse-animal.html
Figure 2: http://www.reptilesupplyco.com/wholesale-fruit-flies/3005-fruit-flies-d-melanogaster-4-cups.html
Figure 3: https://www.britannica.com/science/yeast-fungus
Figure 4: https://academic.oup.com/hmg/article/18/4/667/601791
Figure 5: https://academic.oup.com/hmg/article/18/4/667/601791
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