1 Definition and purpose
A model organism is a non-human species used extensively in biological research to investigate fundamental processes that may also occur in other organisms. The term usually refers to species that are easy to maintain in the laboratory, have well-described biology, and offer practical advantages for experimentation. Researchers study them to uncover general principles of life rather than features unique to one species.
Model organisms serve as experimental systems for asking controlled questions about genes, cells, development, physiology, and disease. Their value lies in the expectation that insights from one species can inform understanding of related mechanisms in others, including humans. This makes them central tools in genetics, medicine, and many branches of experimental biology.
1.1 Scientific role of model organisms
Model organisms provide a manageable way to test biological hypotheses. Because their life cycles, genetics, and anatomy are often well known, investigators can isolate variables more easily than in many larger or less tractable species. This allows detailed study of processes such as cell division, inheritance, tissue development, and responses to environmental change.
They also help connect molecular findings to whole-organism traits. A gene identified in a microorganism or animal can often be traced to a related gene in another species, where it may perform a similar function. For this reason, model organisms are used not only to describe biology, but also to predict how biological systems behave across species boundaries.
1.2 Criteria for selecting a model organism
The choice of a model organism depends on the scientific question being asked. Some species are ideal for rapid genetic screening, while others are chosen because their organs or developmental stages resemble those of target species more closely. In practice, a successful model combines biological relevance with experimental convenience.
Researchers also consider whether the species has an established research community. Widely used models often benefit from standardized methods, shared resources, and extensive reference data, which further increases their utility.
1.2.1 Ease of maintenance
An effective model organism should be simple and economical to culture. Small body size, modest space requirements, and tolerance of laboratory conditions reduce the burden of husbandry. Species that can be grown on defined media or in controlled aquatic or terrestrial environments are especially useful for routine research.
Ease of maintenance also includes resilience and predictable health under laboratory conditions. Organisms that survive handling well and reproduce reliably can support long-term experiments with fewer losses.
1.2.2 Reproductive rate and lifecycle
Short generation times are highly advantageous because they allow researchers to observe inherited traits across multiple generations quickly. Species that produce many offspring can support large-scale experiments and statistical analysis. Rapid development is also valuable in studies of embryology and mutation screening.
A well-characterized lifecycle helps investigators stage experiments consistently. When the timing of developmental transitions is known, comparisons across individuals and laboratories become more reliable.
1.2.3 Genetic tractability
Genetic tractability refers to the ease with which genes can be studied, altered, or tracked. Species with sequenced genomes, efficient transformation systems, and available mutant lines are especially attractive for modern biology. Tools such as transgenesis, mutagenesis, RNA interference, and genome editing expand the range of possible experiments.
Strong genetic tractability allows researchers to connect specific genes to observable traits. This is one of the main reasons certain organisms became standard laboratory models.
1.2.4 Similarity to target species
A model organism is often chosen because it shares important features with the species of interest. These may include conserved genes, comparable cell types, similar developmental pathways, or related organ structures. The closer the match, the more likely the findings are to translate across species.
Similarity does not need to be complete for a model to be useful. Even distant species can reveal ancient biological mechanisms that remain conserved across evolution.
1.3 Historical development of the concept
The use of species as experimental models developed gradually as biology became more laboratory-based. Early naturalists and physiologists studied accessible organisms to answer broad questions about life, inheritance, and development. Over time, specific species became associated with particular research traditions because they were practical and informative.
In the twentieth century, model organisms became especially important in genetics and developmental biology. As molecular tools improved, the same species were adopted in fields such as neurobiology, immunology, and disease research. Today, the concept includes not only traditional animal models but also microorganisms and plants used to study general biological mechanisms.
2 Types of model organisms
Model organisms span a wide range of life forms, from single-celled microbes to mammals and plants. Each group offers different strengths. Microorganisms are often used for rapid molecular studies, invertebrates for developmental and genetic analysis, vertebrates for physiology and disease, and plants for growth, signaling, and crop-related research.
2.1 Microorganisms
Microorganisms are among the most widely used model systems because they grow quickly, are relatively inexpensive, and can be manipulated genetically with ease. Their simplicity makes them ideal for studying core cellular processes, while their molecular pathways often have clear counterparts in more complex organisms.
2.1.1 Bacteria
Bacteria are essential models for understanding gene regulation, metabolism, replication, and cell division. Species such as Escherichia coli became foundational laboratory organisms because they grow rapidly and are straightforward to culture. They are particularly useful for studying molecular biology, protein production, and the effects of mutations.
Bacterial models have also been valuable in research on antibiotic action, plasmids, and horizontal gene transfer. Their compact genomes and efficient genetic tools make them central to biotechnology as well as basic science.
2.1.2 Yeast
Yeasts are single-celled fungi that combine microbial simplicity with eukaryotic cell organization. Saccharomyces cerevisiae is a major model for cell cycle control, DNA repair, intracellular trafficking, and protein quality control. Because yeast cells share many conserved pathways with animals, they are often used to explore processes relevant to human cells.
Yeast models are especially useful in genetics because they can be manipulated rapidly and systematically. Their role in fermentation also made them familiar to scientists long before they became standardized laboratory organisms.
2.2 Invertebrate animals
Invertebrates offer a middle ground between microbial simplicity and the complexity of vertebrates. They are often selected for developmental studies, nervous system research, and large-scale genetic analysis. Many have short lifecycles and produce abundant offspring, making them efficient experimental systems.
2.2.1 Nematodes
Nematodes, especially Caenorhabditis elegans, are widely used for developmental genetics, neurobiology, and aging research. Their transparent bodies make internal structures easy to observe, and their cells have been mapped in great detail. This has made them a powerful system for studying cell lineage and programmed cell death.
Their compact genome and regular development support precise experimental design. Nematodes are also used to investigate sensory behavior, gene regulation, and host-pathogen interactions.
2.2.2 Fruit flies
Fruit flies, particularly Drosophila melanogaster, have been central to genetics for more than a century. They are valued for their short generation time, large brood size, and rich mutant resources. Many foundational discoveries in inheritance, development, and signaling pathways were made with this species.
Fruit flies remain important in studies of neural circuits, circadian rhythms, behavior, and disease mechanisms. Their genetic tools allow researchers to activate, silence, or modify specific cell populations with high precision.
2.2.3 Other arthropods
Other arthropods, including mosquitoes, beetles, and crustaceans, are used when a different ecological or physiological feature is needed. Some serve as models for insect development, sensory biology, or vector-host interactions. Others are studied for molting, segmentation, or environmental adaptation.
These species may be selected when fruit flies are not the best fit for a question. Their diversity allows comparative studies across closely related forms with distinct life histories.
2.3 Vertebrate animals
Vertebrate models are often chosen when researchers need tissues, organs, or developmental programs that more closely resemble those of humans and other mammals. They are especially important in medicine, physiology, and translational research, although they generally require more resources than simpler model systems.
2.3.1 Fish
Fish models, especially zebrafish, are widely used in developmental biology, genetics, and disease studies. Zebrafish embryos develop externally and are transparent at early stages, making them ideal for observing organs as they form. Their rapid development and genetic accessibility have made them a standard vertebrate laboratory model.
Fish are also useful in studies of regeneration, cardiovascular biology, and behavior. Because they are vertebrates, they offer a useful balance between experimental practicality and anatomical complexity.
2.3.2 Amphibians
Amphibians, particularly frogs, have long been used in studies of embryology and cell differentiation. Their large eggs and externally developing embryos made them valuable in early developmental experiments. They continue to serve as models for pattern formation, tissue induction, and regeneration.
Amphibian systems are also used to study oocyte biology and early vertebrate development. Their size and developmental visibility have historically made them important teaching and research organisms.
2.3.3 Rodents
Rodents, especially mice and rats, are the principal mammalian model organisms in biomedical research. They are used to study physiology, genetics, behavior, immunity, and many disease processes. Their mammalian organ systems make them especially relevant for questions that require close comparison with human biology.
Mice are particularly important because of the availability of inbred strains, knockout lines, and targeted genetic tools. Rats are often favored in physiology, pharmacology, and behavioral studies because of their size and handling characteristics.
2.3.4 Other mammalian models
Other mammals, such as rabbits, guinea pigs, pigs, and nonhuman primates, are used for specialized research questions. Some are valuable because of anatomical features, reproductive biology, or immune similarities. Others are chosen for organ size, surgical accessibility, or specific disease models.
These organisms are generally used when rodent models do not adequately represent the biological system under study. Their use is often more selective because of higher cost and husbandry demands.
2.4 Plant models
Plant model organisms are used to study growth, development, stress responses, and gene regulation in photosynthetic organisms. They have contributed greatly to understanding flowering, hormone signaling, and genome organization. Plant models are also important in agriculture and crop improvement.
2.4.1 Flowering plants
Arabidopsis thaliana is the best-known flowering plant model. It has a small genome, a short lifecycle, and a wealth of genetic tools. Researchers use it to investigate leaf formation, flowering time, root development, and responses to light and hormones.
Its value lies in being a simple but informative representative of higher plants. Many of its pathways are conserved across other flowering species, making it a useful reference system.
2.4.2 Crop relatives
Relatives of major crops are used to study traits relevant to agriculture, such as drought tolerance, disease resistance, and nutrient use. These models help bridge basic plant biology and applied crop science. They can reveal how domestication and selection have altered developmental and physiological traits.
Such species are particularly important when a researcher wants to understand how a trait may function in a crop lineage. They can also help identify genes useful for breeding and improvement.
3 Applications in research
Model organisms are used across nearly every major field of biology. Their importance lies not only in describing organism-specific traits, but in uncovering general rules that apply across many species. They are especially valuable in experiments that require controlled genetic backgrounds or rapid observation of inherited changes.
3.1 Genetics and genomics
Genetics and genomics are core areas of model organism research. These species allow scientists to identify genes, determine their function, and compare genomes across evolutionary distances. Because many models have sequenced genomes and robust laboratory tools, they are ideal for connecting DNA variation to biological outcomes.
3.1.1 Mutant analysis
Mutant analysis involves studying organisms with altered genes to infer gene function. By observing changes in development, physiology, or behavior, researchers can determine what a gene normally does. This method has been fundamental in linking genes to traits in microbes, invertebrates, and vertebrates.
Mutants may arise naturally or be created deliberately. Their usefulness depends on clear phenotypes and reliable ways to compare altered and normal organisms.
3.1.2 Gene editing
Gene editing enables targeted changes to DNA, allowing precise testing of gene function. Modern tools make it possible to insert, delete, or modify sequences in many model organisms. This has expanded experimental design beyond traditional breeding and random mutagenesis.
Gene editing is especially powerful when combined with established model systems. It can be used to recreate disease-associated variants, label cells, or study regulatory elements.
3.1.3 Comparative genomics
Comparative genomics examines similarities and differences among genomes from different species. Model organisms serve as reference points for identifying conserved genes and pathways. This helps researchers trace the evolutionary history of biological systems and predict gene function in less-studied species.
Comparative studies also reveal how genomes change over time. They are useful for distinguishing universal mechanisms from lineage-specific adaptations.
3.2 Developmental biology
Developmental biology uses model organisms to investigate how a single cell becomes a complex body. Species with visible embryos or well-mapped cell lineages are especially valuable. These systems help explain how tissues, organs, and body plans arise.
3.2.1 Embryonic development
Embryonic development is one of the most common uses of model organisms. Researchers examine how fertilized eggs divide, pattern themselves, and form tissues. Transparent embryos or large eggs make it easier to observe these processes directly.
Comparisons among species help identify which developmental events are conserved and which are unique. This has clarified many basic principles of animal and plant development.
3.2.2 Cell fate determination
Cell fate determination refers to the process by which cells acquire specialized identities. Model organisms allow scientists to track how signals and gene networks guide these decisions. This work has revealed how one cell becomes a neuron, muscle cell, blood cell, or other specialized type.
Understanding cell fate is important for both development and regenerative biology. It also informs stem cell research and tissue engineering.
3.2.3 Organ formation
Organ formation studies how tissues assemble into functional structures such as the heart, brain, kidney, or leaf. Model organisms are useful because they permit direct observation and experimental manipulation during these stages. Researchers can test how shape, signaling, and cell movement contribute to organ development.
These studies often reveal conserved developmental modules. They are important for understanding congenital abnormalities and growth defects.
3.3 Physiology and anatomy
Model organisms help scientists investigate how bodies function as integrated systems. Their anatomy and physiology can be measured under controlled conditions, making them suitable for studying organs, metabolism, and lifespan. Some species are chosen because a particular system is especially accessible or experimentally tractable.
3.3.1 Organ system function
Organ system function includes the study of the nervous, circulatory, respiratory, digestive, and reproductive systems. Vertebrate models are especially useful here because they share many organ-level features with humans. However, invertebrates can also provide insights into simpler versions of these systems.
Researchers often use these models to examine physiology at multiple scales, from cells to whole organisms. This helps link molecular mechanisms to organ performance.
3.3.2 Metabolism
Metabolism research in model organisms covers energy use, nutrient processing, and biochemical regulation. Yeast, worms, flies, and rodents have all contributed to this field. Their different levels of complexity allow investigators to compare metabolic control across life forms.
Model systems are useful for studying metabolic pathways, nutrient sensing, and the effects of diet or genetic alteration. They also help identify conserved regulators of energy balance.
3.3.3 Aging studies
Aging studies use model organisms to explore how lifespan is regulated and why function declines with age. Short-lived species are especially informative because they permit rapid testing of long-term biological hypotheses. Worms, flies, yeast, and mice have all played major roles in this area.
These studies focus on processes such as stress resistance, DNA repair, protein maintenance, and cellular senescence. Findings from model systems have shaped broader theories of aging.
3.4 Disease modeling
Model organisms are widely used to study disease mechanisms in controlled settings. They can mimic aspects of human disorders, reveal how symptoms arise, and provide platforms for testing interventions. While no model perfectly reproduces a human disease, many capture key features of its biology.
3.4.1 Cancer research
Cancer research in model organisms examines cell proliferation, DNA damage, tumor suppressor function, and abnormal signaling. Mice, fish, flies, and worms can all be used to study oncogenic pathways. These models help identify genes that promote or restrain uncontrolled growth.
They are also valuable for observing tumor progression and therapeutic response. Experimental systems make it possible to test cause-and-effect relationships that are difficult to establish in patients.
3.4.2 Neurodegenerative disease
Neurodegenerative disease models are used to study the loss of neurons and associated protein misfolding, inflammation, and cellular stress. Rodents and zebrafish are common vertebrate models, while flies and worms are useful for genetic screening. These systems help reveal mechanisms underlying disorders affecting memory, movement, and neural integrity.
Although models differ from human disease in important ways, they can reproduce selected molecular features. This makes them useful for identifying candidate pathways and therapeutic targets.
3.4.3 Infectious disease
Infectious disease research uses model organisms to examine host-pathogen interactions, immune responses, and microbial virulence. Bacteria, yeast, invertebrates, and vertebrates each contribute different perspectives. Some models are used to study the pathogen directly, while others help analyze the host response.
These systems can clarify how infections spread, how immune defenses operate, and why some hosts are more susceptible than others. They also support screening for antimicrobial compounds.
3.4.4 Metabolic disorders
Metabolic disorder models are used to study conditions involving altered glucose handling, lipid regulation, obesity-related traits, and related pathways. Rodents are especially common, but flies, worms, and fish also contribute. They allow researchers to investigate genetic and environmental influences on metabolism.
Such models are useful for exploring how diet, hormones, and cellular signaling interact. They also support the search for preventive and therapeutic strategies.
3.5 Drug discovery and toxicology
Model organisms are important in early drug discovery and safety testing. They can be used to screen compounds for biological activity, assess side effects, and evaluate toxicity under controlled conditions. Their rapid lifecycles and genetic consistency make them efficient for comparative testing.
In toxicology, models help identify whether a substance affects development, behavior, organs, or survival. In drug discovery, they can reveal whether a compound has the desired effect before more complex studies are undertaken. This reduces cost and can improve the selection of promising candidates.
4 Advantages and limitations
Model organisms are powerful experimental systems, but they are not universally applicable. Their usefulness depends on matching the organism to the question. Each model offers clear practical advantages while also carrying biological constraints that must be considered when interpreting results.
4.1 Experimental advantages
Model organisms provide repeatable, controlled settings for hypothesis testing. Their established methods and standardized backgrounds often make experiments easier to design and compare across laboratories. This efficiency is one reason they have become central to modern biology.
4.1.1 Short generation time
Many model organisms reproduce quickly, allowing researchers to observe inherited traits and developmental changes over short periods. This speed is especially valuable in genetics and evolution studies. It also enables large-scale screens that would be impractical in slower-growing species.
Short generation time can accelerate discovery by allowing rapid testing of multiple generations or many genetic variants.
4.1.2 Low cost
Compared with many larger animals, model organisms are often inexpensive to house and study. Small size, simple feeding requirements, and compact facilities reduce overall research costs. Lower expense makes it feasible to maintain larger sample sizes and replicate experiments.
Cost efficiency has helped make some models standard across many disciplines. It also allows laboratories with modest resources to participate in advanced biological research.
4.1.3 Experimental control
Model systems give researchers substantial control over environment, genetics, and developmental stage. This makes it easier to identify causal relationships. Controlled conditions also reduce noise from variable backgrounds, which improves the clarity of experimental outcomes.
Such control is particularly valuable in mechanistic studies. It helps distinguish direct effects from secondary or accidental ones.
4.2 Biological limitations
Despite their utility, model organisms cannot reproduce all aspects of other species. Differences in anatomy, physiology, and gene regulation may limit how widely results can be applied. Careful interpretation is therefore essential.
4.2.1 Species-specific differences
Every species has unique traits that may affect how a biological process operates. A gene or pathway conserved in broad outline may still behave differently in different organisms. These distinctions can influence development, metabolism, and disease.
Species-specific differences are not flaws in the model so much as boundaries on its scope. They define what can and cannot be inferred from a given system.
4.2.2 Incomplete translational relevance
Findings in a model organism do not always translate directly to humans or other target species. A mechanism may be conserved, but its clinical or ecological context may differ. For this reason, model-based results usually require confirmation in additional systems.
Incomplete translational relevance is particularly important in biomedical research. It encourages the use of multiple complementary models rather than reliance on a single organism.
4.2.3 Ethical and practical constraints
Some questions cannot be addressed ethically or practically in certain species. Larger animals may raise higher welfare concerns, require specialized facilities, or be too costly for extensive screening. These constraints influence which organisms can be used and how experiments are designed.
Such limits often lead researchers to begin with simpler models before moving to more complex ones. This staged approach improves feasibility and reduces unnecessary use of higher-order animals.
5 Husbandry and laboratory use
The laboratory value of a model organism depends not only on its biology but also on how it is maintained. Reliable husbandry practices support health, reproducibility, and experimental consistency. Standardized care is a major reason model organisms remain useful across many institutions.
5.1 Housing and care
Housing requirements vary widely among species. Microorganisms need defined culture conditions, while animals require regulated temperature, humidity, nutrition, and sanitation. Plants need controlled light, water, and growth media. Proper care is essential for keeping organisms healthy and minimizing confounding stress.
In many laboratories, husbandry is tailored to life stage and experimental purpose. Care routines are designed to preserve biological normality as much as possible.
5.2 Breeding and colony management
Breeding strategies are important for maintaining stable populations and desired genetic backgrounds. Inbred lines, outbred populations, and transgenic stocks each require different management approaches. Accurate records of parentage, genotype, and age help preserve experimental reliability.
Colony management also includes preventing contamination, genetic drift, and unplanned mixing of lines. Good practices are necessary to keep stock characteristics consistent over time.
5.3 Standardization and reproducibility
Standardization reduces variation between experiments and laboratories. Common protocols for feeding, temperature, light cycles, and handling improve reproducibility. The use of reference strains and shared methods helps ensure that findings can be compared reliably.
Reproducibility is especially important in fields that rely on subtle phenotypes. Small differences in conditions can otherwise produce misleading results.
5.4 Genetic stocks and repositories
Genetic stock centers preserve mutant lines, transgenic strains, and reference populations. These repositories make it possible for researchers worldwide to obtain standardized material. They also reduce duplication of effort by centralizing strain maintenance.
Repositories are vital for long-term continuity in model organism research. Without them, many specialized lines would be lost or difficult to verify.
6 Data resources and research infrastructure
Modern model organism research depends on digital databases, curated strain collections, and collaborative networks. These resources allow scientists to share data, annotate genes, and compare results across species. Infrastructure has become as important as the organisms themselves in sustaining biological research.
6.1 Genomic databases
Genomic databases provide access to sequences, gene models, mutations, and functional annotations. They are essential for interpreting experimental results and designing new studies. Many databases also include expression data, protein information, and links to literature.
These resources make it easier to integrate molecular findings with organism-level biology. They are indispensable for comparative and functional genomics.
6.2 Strain collections
Strain collections preserve defined lines for future use. They are often organized by species and maintained under standardized conditions. Availability of authenticated strains helps ensure that experiments can be repeated and verified.
Such collections are especially important when a line carries a specific mutation or transgene. Researchers depend on them for continuity and reproducibility.
6.3 Community research consortia
Research consortia coordinate large-scale projects, shared standards, and collaborative tool development. They help unify methods within a research community and support the exchange of data and biological resources. These groups often play a major role in creating community-wide reference tools.
Consortia also encourage communication among laboratories working on the same model organism. This can speed discovery and reduce duplication.
6.4 Reference annotations
Reference annotations describe genes, transcripts, regulatory features, and other genomic elements. They provide a common framework for interpreting data across studies. High-quality annotations are crucial when comparing mutants, expression profiles, or evolutionary conservation.
As knowledge improves, reference annotations are updated to reflect new evidence. This ongoing curation helps keep model organism databases scientifically useful.
7 Ethical considerations
Ethical issues arise whenever living organisms are used in research, especially animals with greater capacity for pain or distress. Ethical frameworks aim to balance scientific benefit with welfare, responsibility, and transparency. These concerns shape how experiments are approved and conducted.
7.1 Animal welfare in research
Animal welfare involves minimizing pain, distress, and unnecessary harm. Researchers are expected to use appropriate care, anesthesia, and humane endpoints when needed. Welfare oversight helps ensure that scientific goals do not override basic ethical obligations.
Attention to welfare can also improve data quality. Healthy, well-treated organisms are more likely to produce reliable results.
7.2 Replacement, reduction, and refinement
The principles of replacement, reduction, and refinement guide responsible animal research. Replacement seeks non-animal alternatives when possible. Reduction aims to use the fewest animals needed for valid conclusions. Refinement focuses on improving procedures to lessen suffering and improve welfare.
These principles are widely applied in model organism work. They encourage careful experimental design and continual improvement of methods.
7.3 Regulatory oversight
Research involving model organisms is commonly subject to institutional and national oversight. Review processes assess scientific justification, animal care, and procedural safeguards. Regulations vary by species and jurisdiction, but they generally require documentation and monitoring.
Oversight provides accountability and helps align research practices with ethical and legal standards. It also supports public trust in laboratory science.
8 Representative model organisms
Several species have become especially prominent as standard laboratory models. Each represents a different branch of life and a different style of research utility. Together they illustrate the breadth of modern model organism science.
8.1 Escherichia coli
Escherichia coli is a bacterial model central to molecular biology, genetics, and biotechnology. It grows rapidly, is easy to manipulate, and has been used extensively to study DNA replication, transcription, translation, and metabolism. It also serves as a workhorse for cloning and protein expression.
Its long history in laboratory research has made it one of the best-understood organisms in science. Many basic laboratory techniques were developed or refined with this bacterium.
8.2 Saccharomyces cerevisiae
Saccharomyces cerevisiae, or baker’s yeast, is a key eukaryotic model organism. It has been used to investigate the cell cycle, chromosome biology, vesicle transport, and stress responses. Because it is a fungus, it provides insight into eukaryotic cellular organization while remaining experimentally simple.
Yeast has also been important in industrial fermentation. Its dual value in basic science and applied work has supported decades of intensive study.
8.3 Caenorhabditis elegans
Caenorhabditis elegans is a nematode widely used in development, neurobiology, and aging research. Its transparent body, fixed cell lineage, and compact genome make it exceptionally tractable. Researchers use it to study apoptosis, neural function, and gene regulation.
Its small size and rapid lifecycle make it well suited to high-throughput experimentation. It has become a classic model for linking genes to behavior and development.
8.4 Drosophila melanogaster
Drosophila melanogaster is one of the most influential model organisms in biology. It played a major role in establishing modern genetics and continues to support research in development, neuroscience, and disease mechanisms. Its genetic tools and abundant mutant resources make it highly versatile.
The fruit fly is especially important for studying conserved signaling pathways. Many discoveries first made in flies have later been confirmed in other animals.
8.5 Danio rerio
Danio rerio, or zebrafish, is a vertebrate model used for developmental biology, genetics, and biomedical research. Its transparent embryos and external development make early stages easy to observe. It is also useful in studies of regeneration, organ formation, and behavioral biology.
Zebrafish bridge the gap between simple invertebrate models and mammals. Their accessibility has made them a prominent vertebrate system for modern research.
8.6 Mus musculus
Mus musculus, the laboratory mouse, is the principal mammalian model in biomedical science. It is used to study genes, tissues, physiology, immunity, behavior, and disease. The availability of inbred strains and sophisticated genetic engineering has made it exceptionally powerful.
Because it is a mammal, the mouse is often chosen when organ systems or developmental processes need close relevance to humans. Its central role in translational research is unmatched among model animals.
8.7 Arabidopsis thaliana
Arabidopsis thaliana is the leading plant model organism. Its short generation time, small genome, and ease of genetic manipulation make it ideal for studying plant development and signaling. It has contributed to major advances in flowering biology, hormone responses, and stress physiology.
As a reference plant, it helps researchers connect basic molecular findings to broader plant biology. Its influence extends from fundamental science to agriculture.
9 See also
Model organism Laboratory animal Genetics Developmental biology Genomics Comparative genomics Molecular biology Transgenesis Gene editing Inbred strain Repository Biological database