Meet the 8 most used experimental subjects at VIB

28 September 2016

The 8 most used experimental subjects at VIB.

Each science field or research scope requires the best-fitting model, and each one comes with perks and limitations. Let’s take a microscopic look at the most common lifeforms VIB scientists are using to contribute to better lives.

Arabidopsis Thaliana
Arabidopsis thaliana is a type of cress native to Eurasia, and often considered a weed. But in the world of science, it is the model organism used to explore the molecular biology of plant characteristics. The plant can complete its life cycle in just 6 weeks, and many mutants are available to easily and quickly achieve desired characteristics. It also takes up very little space compared with alternative plant models such as corn or rice, and many seeds can be germinated on a small surface. However, a microscope is necessary for many observations, and it can be difficult to handle and isolate tissues. Because Arabidopsis is only a model organism, the agricultural applicability of results should always be confirmed in one or more economically relevant crops.

Corn has become an important food crop around the world, as it easily grows in a variety of climates and conditions. As a result, it is an important model organism for the translation of research-based processes into real applications. It also has particular physical characteristics that make it useful in research, such as large leaf size and growth patterns that allow for high-resolution samples and easy molecular analysis. Because corn is useful in both the field and the lab, these two environments can easily be compared, for even more in-depth insights into conditions, processes and changes. However, corn is time, labor and space-consuming to grow and transform compared with other plant models. Even so, gene editing processes are smoothly conducted in corn, which could lead to a variety of new research opportunities using growing mutant collections.

Drosophila Melanogaster
Also known as the fruit fly, Drosophila melanogaster has a brain and nervous system that are just as complex as those of vertebrates, and capable of sophisticated behaviors such as sleep and learning, even as larva. Because its neuronal function and synaptic molecules are easy to study, it is an ideal model for revealing synaptic pathways and neuronal functions that are disturbed in neurodegenerative diseases. In addition, many aspects of neural development and function are similar between invertebrates and vertebrates, including humans. Not only are fruit flies fast-breeding and easy to handle in large numbers, researchers have a huge repertoire of genetic tools available, enabling them to reproducibly work with each neuron in a complete, living animal.

Poplar is a commercial tree species that is cultivated worldwide in plantations for pulp and paper, veneer, packing material, lumber and energy. It is a fast-growing tree that can be vegetatively propagated, and this is also one of the reasons why it has become an excellent model system for research on trees. Furthermore, it has a small genome that has been sequenced, and it can be easily transformed. The new CRISPR/Cas9 genome editing technique works very efficiently in poplar. Because poplars grow fast and can be grown on marginal soils, they are a promising alternative to fossil resources for the production of biofuels and other biobased products in the biorefinery.

Rats and Mice
These furry rodents are instrumental in the study of human health and disease, as we share many of the same developmental, anatomical and physiological traits and patterns. Almost every human gene has its “mouse version”, and both types of genes are similar in structure, regulation and genome organization. Rats and mice are easily cared for and give birth to large litters, and there are a variety of bred lines to choose from, leading to more reliable research. The genomes of mice and rats are efficiently changed, although creating a genetically-modified mouse or rat is a time-consuming process compared with other simpler models available. Rats and mice must be provided with friendly care and a warm, peaceful and quiet environment to maintain high birth rates and the excellent health needed to be part of a study.

Xenopus Tropicalis
Xenopus tropicalis is a small aquatic frog native to Africa. Unlike Drosophila, which has been used in research for over a century, Xenopus is a relatively new model organism which, as a vertebrate, offers significant advantages and opportunities to researchers, and is often used alongside rosophila to translate insights from Drosophila research into relevant pathways in humans. Other key features include: neural wiring in embryos is easily observed; female frogs produce thousands of eggs that develop into tadpoles within days, and; the genome sequence of Xenopus is well-known and contains no gene duplications, which can confound genetic modification.

We’re all familiar with everyday applications of yeast such as bread and beer, but it is also often used as a model organism to study different aspects of cell biology. Classified as a fungus, yeast cells respond on a unicellular level to changes in nutrient levels, and the responses are
clearly observable, leading to insights about cell biology that can be translated to effects in higher organisms. Yeast reproduces rapidly and is very undemanding when it comes to care. As one of the most studied unicellular organisms, its genome is completely known and easily modified via large numbers of gene libraries.

A small, striped, freshwater minnow, the zebrafish is often chosen as a model in research concerning cancer, drug discovery and the human vascular system. Unlike other animal models such as Drosophila and Xenopus, the zebrafish has a simple cardiovascular system with an anatomy similar to that in humans. Other advantages of using zebrafish as models include constant size during development, embryo transparency and external fertilization for easy visualization of internal organs, and very fast genetic manipulation. However, as fish, they do lack important mammalian organs such as lungs as well as the divergent immunological elements essential for many common human diseases.

Go back to the front page: 'No model, no research: why models are at the core of VIB science'

Corn © VIB, 2016
Front row from left to right:
Charlot Versteele, Hilde Nelissen, Kirin Demuynck, Jolien De Block, Xiaohuan Sun

Back row from left to right:
Tom Van Hautegem, Lennart Verbraeken, Kim Feys, Bernard Cannoot, Hironori Takasaki, Nathalie Wuyts (VIB-UGent)