Model organisms are of high importance for contemporary scientific achievements. By definition, they are usually easily handled, extensively tested and fully understood eukaryotic or prokaryotic organisms that can be used for scientific experiments. According to the principles of evolution, all the living organisms on Earth have a common ancestor, which signifies that they all share common genetic characteristics. In other words, they carry similar DNA information. For that reason, the results of a survey on models can be taken into consideration for medical purposes for other organisms, especially for humans.
Animals have been used as models in science since antiquity. A treatment for almost all of the human diseases has been discovered after laboratory tests on experimental animals. Such models can be homologous to humans for a specific disease, meaning that they can have the same causes, symptoms and treatments. They can also be isomorphic, sharing only similar symptoms and treatments with human patients. Or they can be predictive, with less similar characteristics in the response but higher chances to help find the basic biopaths and mechanisms of action that are activated during specific health conditions. Today, there are several model organisms that help to solve medical questions and increase the level of science.
Drosophila melanogaster, commonly known as fruit fly, is one of the oldest model organisms to be chosen in molecular genetic studies. Thomas Hunt Morgan identified the important role of chromosomes as genetic information carriers in his studies in the early 30s. Τhis decisive discovery laid the foundations for experimental science. The fly has a short life, multiple mating periods and numerous offspring. At the same time, specific phenotypical characteristics, like body color, shape of wings and number of antennas can be easily noticed. That means that drosophila is a very good model to study genetics as the information carried through the DNA is imprinted in the external characteristics of the numerous insects in labs, so just a simple observation can lead to informative data.
The most famous of all the experimental animals and model organisms is the mouse. Mus musculus is a mammalian rodent that is small in size, easy-handled and human friendly. Usually labs create transgenic animal lines by changing the genetic information of the newborns, or create the needed individual animals by special breeding of animals with specific characteristics. Matings among mice lead to the birth of numerous animals which is really important for the time frame of an experimental project. Even though it is difficult to believe, the mouse’s genome is highly relevant to human DNA. In fact, that makes the organism a perfect model to study genetics. Many life-threatening genetic disorders, as well as the heritability of diseases, have been extensively studied with the aid of mice. Furthermore, psychological and behavioral experiments are also finding answers to main questions after experimenting on mice. Rats are also animals very similar to mice that are quite commonly used in experiments as well. By experience, it is safe to claim that they are friendlier and more relaxed compared to mice, despite the fact that they are usually of a larger size.
Fish also gained an important place in the list of the most important model organisms for science. Especially Zebrafish, or Danio rerio, which is an extremely small aquarium fish that attracted a lot of lab groups to choose it as a model for their surveys. Since its first use in the 1970s, Zebrafish have aided in the collection of important scientific data in the genetic field. Contemporary studies use it mostly for drug analysis tests and preclinical applications. Psychology studies have also used this fish, especially for memory tests. Danio rerio is also good for visual observation, under microscope or even with the naked eye, as the transparent body of the fish makes the study of its inner parts easier. Some labs are able to create transgenic strains that are easily handled and provide the opportunity to use the fish in a wider variety of experiments. Similar to almost all of the model organisms, zebrafish have multiple reproduction periods during their life and generate hundreds of embryos that grow rapidly.
Apart from the aquatic models, Caenorhabditis elegans is a surprisingly helpful model organism for laboratory experiments. Basically, c. elegans is a nematode worm of extremely small size (about 1mm). Despite the fact that it lacks basic organ systems, such as respiratory and circulatory systems, its nervous system is quite developed and the simplest among all organisms that have a nervous system. It started being a model organism in the early 70s’, especially in neuroscience studies. Throughout the years, Impressive studies about ageing and basic molecular systems in organisms have been published. The worm also has a transparent body that helps ease the visual observation of the inner development of the organs. Its reproduction can also facilitate studies because c. elegans is hermaphroditus, producing both male and female cells important for the creation of offspring. They also have a low cost of maintenance, which is also an advantage that helps labs be able to afford to use it as a model organism.
There are quite many different opinions about whether it is ethical or not to use animals in science, but history proves the invaluable knowledge that has been gained over the years from animal studies. Believe it or not, there is a remarkably high relevance among the genetic information between humans and some animals, despite the difference in appearance between these different species. Model organisms provide a great advantage to research as basic biological phenomena. They are also important when medical conditions are extensively studied, before clinical trials and applications take place. Consequently, it is reasonable to claim that animals and model organisms help improve the understanding and protection of life.