What are model organisms?
Model organisms are well-studied species that can be easily maintained in a laboratory setting. Which model organism is chosen for a particular study depends on what is being studied. For example, frogs are often used in embryonic studies due to their larger, more transparent embryos. [1]
Why do we need model organisms?
There are many reasons why we need model organisms including, but not limited to:
How is a model organism chosen?
Several questions are asked when choosing a model organism. Some questions to consider are:
Why do we need model organisms?
There are many reasons why we need model organisms including, but not limited to:
- Easily maintained in a laboratory setting
- Easy to breed for specific genotypes or phenotypes
- Short generation time
- Similar or identical biological processes to humans
How is a model organism chosen?
Several questions are asked when choosing a model organism. Some questions to consider are:
- Does this organism mimic the human process you wish to study?
- Is there a homologous gene or protein in this organism?
- Is there an existing genotype/phenotype specific line that can be used or can a specific line be generated?
- Are there any special characteristics that will aid you in performing your experiments?
Common Model Organisms
Yeast
Saccharomyces cerevisae
Yeast is a single-celled eukaryotic organism that is cheap and easy to use in the laboratory. It is very well-studied and divides rapidly. Despite its different makeup, it has a lot of similarity to other eukaryotes and has been used extensively to study the cell cycle and metabolism. [1]
Yeast Database
Saccharomyces cerevisae
Yeast is a single-celled eukaryotic organism that is cheap and easy to use in the laboratory. It is very well-studied and divides rapidly. Despite its different makeup, it has a lot of similarity to other eukaryotes and has been used extensively to study the cell cycle and metabolism. [1]
Yeast Database
Fruit Fly
Drosophila melanogaster
Fruit flies are great model organisms for large genetic screens. They have a fast generation time and are well-studied. They have been used extensively to study everything from behavior, circadian rhythms, to amyotrophic lateral sclerosis (ALS). [1]
Fly Database
Drosophila melanogaster
Fruit flies are great model organisms for large genetic screens. They have a fast generation time and are well-studied. They have been used extensively to study everything from behavior, circadian rhythms, to amyotrophic lateral sclerosis (ALS). [1]
Fly Database
Nematode
Caenorhabditis elegans
Nematodes are worms that offer unique but useful characteristics for a model organism. They are transparent throughout their life which makes them ideal for microscopy. They also have a male and hermaphrodite sexes that can reproduce via self-fertilization which aids inbreeding for genetic studies. [2]
Nematode Database
Caenorhabditis elegans
Nematodes are worms that offer unique but useful characteristics for a model organism. They are transparent throughout their life which makes them ideal for microscopy. They also have a male and hermaphrodite sexes that can reproduce via self-fertilization which aids inbreeding for genetic studies. [2]
Nematode Database
Zebrafish
Danio rerio
Zebrafish are a more recent model organism. They have a fast generation time and large schools can be kept in a relatively small area. They fertilize their eggs externally which allows good control for genetic experiments. Transparent zebrafish have been made which is useful for microscopy approaches. [3]
Zebrafish Database
Danio rerio
Zebrafish are a more recent model organism. They have a fast generation time and large schools can be kept in a relatively small area. They fertilize their eggs externally which allows good control for genetic experiments. Transparent zebrafish have been made which is useful for microscopy approaches. [3]
Zebrafish Database
Mouse
Mus musculus
Mice have been the quintessential model organism for a long time, mostly due to their high similarity to humans. Mice have the same organ systems as humans and develop the same diseases. This, along with the thousands of different genetic strains that exist, make mice one of the best model organisms to study human disease. [4]
Mouse Database
Mus musculus
Mice have been the quintessential model organism for a long time, mostly due to their high similarity to humans. Mice have the same organ systems as humans and develop the same diseases. This, along with the thousands of different genetic strains that exist, make mice one of the best model organisms to study human disease. [4]
Mouse Database
Rat
Rattus norvegicus
This was the first mammalian species domesticated for scientific research, with work dating back to before 1850. The rat has become the most widely studied experimental animal model for biomedical research [5].
Rat database
Rattus norvegicus
This was the first mammalian species domesticated for scientific research, with work dating back to before 1850. The rat has become the most widely studied experimental animal model for biomedical research [5].
Rat database
What is a good model organism for Hepatic Lipase Deficiency?
Rattus norvegicus is a good model for studying the effects of hepatic lipase deficiency on reproduction as rats ovaries are more similar to humans than those of mice. In addition, they share a progesterone synthesis pathway that is highly similar to humans [6].
Conclusions
Model organisms are an important part of designing experiments. Using the correct model organism allows a scientists to perform assays that they would not be able to in others.
References
[1] What are model organisms? (2017, March 03). Retrieved from https://www.yourgenome.org/facts/what-are-model-organisms
[2] Riddle DL, Blumenthal T, Meyer BJ, et al., editors. C. elegans II. 2nd edition. Cold Spring Harbor (NY): Cold Spring Harbor Laboratory Press; 1997. Section I, The Biological Model. Available from:https://www.ncbi.nlm.nih.gov/books/NBK20086/
[3] Davis, E. E., & Katsanis, N. (2017). Zebrafish: A Model System to Study the Architecture of Human Genetic Disease. Animal Models for the Study of Human Disease,651-670.doi:10.1016/b978-0-12-809468-6.00025-5
[4] Spencer, G. (n.d.). Background on Mouse as a Model Organism. Retrieved from https://www.genome.gov/10005834/background-on-mouse-as-a-model-organism/
[5] Jacob, H. J. (1999). Functional genomics and rat models. Genome research, 9(11), 1013-1016.
[6] Grummer, R. R., & Carroll, D. J. (1988). A review of lipoprotein cholesterol metabolism: importance to ovarian function. Journal of animal science, 66(12), 3160-3173.
Non-linked Figures:
Header: www.ebi.ac.uk/about/news/press-releases/mouse-disease-models
[2] Riddle DL, Blumenthal T, Meyer BJ, et al., editors. C. elegans II. 2nd edition. Cold Spring Harbor (NY): Cold Spring Harbor Laboratory Press; 1997. Section I, The Biological Model. Available from:https://www.ncbi.nlm.nih.gov/books/NBK20086/
[3] Davis, E. E., & Katsanis, N. (2017). Zebrafish: A Model System to Study the Architecture of Human Genetic Disease. Animal Models for the Study of Human Disease,651-670.doi:10.1016/b978-0-12-809468-6.00025-5
[4] Spencer, G. (n.d.). Background on Mouse as a Model Organism. Retrieved from https://www.genome.gov/10005834/background-on-mouse-as-a-model-organism/
[5] Jacob, H. J. (1999). Functional genomics and rat models. Genome research, 9(11), 1013-1016.
[6] Grummer, R. R., & Carroll, D. J. (1988). A review of lipoprotein cholesterol metabolism: importance to ovarian function. Journal of animal science, 66(12), 3160-3173.
Non-linked Figures:
Header: www.ebi.ac.uk/about/news/press-releases/mouse-disease-models