This web page was produced as an assignment for Genetics 564, an undergraduate capstone course at UW-Madison.
What are model organisms? [1,2]
Model organisms are non-human species that are used to study life. They can vary from being very complex such as mice or as simple as yeast. Typically the type of organism that is chosen for an experiment is solely based on the research question, since each species has different characteristics that can be proven useful for studying. Additionally, model organisms are useful because of their similar physiology and genetic makeup to humans. Many species such as zebrafish and mice have homologous genes that when mutated, display similar symptoms and behavioral traits to a diseased human state. The use of such models provides an understanding to the molecular changes that occur with diseases and allows researchers to explore different avenues of therapeutic treatments.
Why are model organisms useful? [1,2]
Not only are model organisms useful proxy to understanding the biological system of humans but they also have other characteristics that make them advantageous. Some common traits and benefits that are shared amongst model organisms include:
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Benefits to commonly used model organisms
Caenorhabditis elegans: [2] C. elegans, also known as the nematode worm, has been used as a model organism since the early 1960s. The anatomy is relatively simple making it easy to study yet has conserved pathways that are found in humans. The worm is cheap, easy to grow in larger numbers, has a short life cycle, and a transparent body making it easy to observe cells with in the organism. Mutants of the nematode worm are often used to model diseases such as neurological disorders, congenital heart diseases, and kidney diseases. |
Drosophila Melanogastor: [2] The fruit fly is very common model organism that is well understood in the academic community. Drosophila have many conserved genes to humans, in fact 75% of genes that play a role in human diseases can be found with in the fruit flies genome. This model organism is beneficial to use in studies because not only are they inexpensive and the biology is well understood from the years of research, but they happen to be easy to observe mutations in and see where chromosomal rearrangements take place (polytene chromosomes). |
Danio Rerio: [2] The zebrafish was first used in the 1960s as a model organism and since then has helped aid in the understanding of many human disorders such as muscular dystrophy and cancer development. One of the financial benifits of zebrafish are that they are cheap and produce many offsprings. The embryos themselves are studied because of their transparency allowing the development of the organism to be observable to the human eye. Similarly to Drosphila, zebrafish have 70% of the same genes as humans most of which can be related to human diseases. Physiologically speaking, zebrafish have the same or similar organs to humans as well making them an ideal candidate for studies. |
Mus Musculus: [2] The mouse is considered the preferred mammalian model for studying, mainly because of its genetic and physiological similarities to humans. Additionally the mice tend to be cost effective and reproduce quickly making it easy to have an abundance of test subjects available. Often times mice are studied for complex diseases because of how similar their biological systems are to humans. Like other model organisms, their genomes are easy to manipulate for genetic studies. |
Which model organism is effective in studying KIF5A?
The zebrafish seems to be the most effective for studying the symptoms of a defective KIF5A gene. Zebrafish are an ideal model in this project because they display many of the same symptoms as hereditary spastic paraplegia when KIF5A is mutated. According to The Zebrafish Information Network (KFIN), an abnormal KIF5A gene causes issues with axonal cargo transport and axonal growth. Use of this model organism could be beneficial understanding why spasticity occurs in the lower extremities of organisms. Additionally, zebrafish are easy to observe making clear if there is any change in the motor function when SP10 is induced. It's also very easy to mutate Zebrafish so that fins of the fish can be abnormally shortened or removed which could be useful in studying KIF5A .
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References:
[1] Using Research Organisms in Health and Diseases. (October 2017). Retrieved from https://www.nigms.nih.gov/Education/Pages/modelorg_factsheet.aspx
[2] What are Model Organisms? (April 3, 2017). Retrieved from https://www.yourgenome.org/facts/what-are-model-organisms
[1] Using Research Organisms in Health and Diseases. (October 2017). Retrieved from https://www.nigms.nih.gov/Education/Pages/modelorg_factsheet.aspx
[2] What are Model Organisms? (April 3, 2017). Retrieved from https://www.yourgenome.org/facts/what-are-model-organisms