Essay !7 - About Model Organims Code : KSI0007
What is Model organism?
A model organism is a non-human species that is extensively studied to understand particular biological phenomena, with the expectation that discoveries made in the organism model will provide insight into the workings of other organisms. The reason why I am writing about model organism is that I am study about the DNA repair mutant zebrafish. So I'm very curious about the model organisms such as c. elegans , e.coli, or drosophila, xenopus and mouse and so on .
Which characteristics are good for model organism?
1. Small, easy and cheap to maintain and manipulate
2. Short lifespan
3. Produce large numbers of offspring
4. Development is external
5. Availability of mutants
6. Lots of history/previous experiments and discoveries
7. Genome is sequences
8. Homologues for with human disease genes are high percentage.
9. Fewer ethical concerns
Why is model organism research useful for studying disease?
The natural course of a disease in a human may take dozens of years. Simple organisms that can develop a disease or some of its symptoms make it possible for researchers to learn about the disease faster—in a period of months to a few years. That would be nearly impossible, and often unethical, to do in humans.
When scientists discover that a particular gene is associated with a disease in humans, one of the first things they typically do is find out what that gene does in a model organism. This often provides important clues for understanding the cause of a disease and for developing potential diagnostic tests and treatments.
Contents
- 1 How has model organism research impacted human health?
- 2 Yeast studies sorted out the orderly sequence of events, called the cell cycle, in which a cell duplicates its contents and divides into two. This information has benefited millions of people, since many drugs used to treat cancer act by interfering with the cell cycle.
- 3 Experiments performed with yeast have also clarified how genes are turned on or off. This knowledge explains how cells that contain the same genes can be so different from one another, which has advanced understanding of both normal developmental processes and diseases that occur when genes are turned on or off at the wrong time or in the wrong cell.
- 4 Studies in fruit flies and tiny worms taught scientists key aspects of how fertilized eggs develop into complex organisms. In the course of these studies, researchers made unanticipated discoveries, such as learning that genetically controlled cell death plays a critical role in cancer and other diseases.
- 5 Research with bacteria, viruses and yeast has revealed how all living things pass on their genes to offspring through copying DNA and fixing mistakes that get made during the copying process.
- 6 Laboratory rats have been used for many decades to test drugs. In addition, much of what we know about cancer-causing molecules was learned through basic research with rats.
- 7 Mice can be genetically engineered to serve as models of Lou Gehrig's disease and many other human illnesses.
- 8 What more can model organism research tell us?
- 9 These are the representative model organisms
How has model organism research impacted human health?
Yeast studies sorted out the orderly sequence of events, called the cell cycle, in which a cell duplicates its contents and divides into two. This information has benefited millions of people, since many drugs used to treat cancer act by interfering with the cell cycle.
Experiments performed with yeast have also clarified how genes are turned on or off. This knowledge explains how cells that contain the same genes can be so different from one another, which has advanced understanding of both normal developmental processes and diseases that occur when genes are turned on or off at the wrong time or in the wrong cell.
Studies in fruit flies and tiny worms taught scientists key aspects of how fertilized eggs develop into complex organisms. In the course of these studies, researchers made unanticipated discoveries, such as learning that genetically controlled cell death plays a critical role in cancer and other diseases.
Research with bacteria, viruses and yeast has revealed how all living things pass on their genes to offspring through copying DNA and fixing mistakes that get made during the copying process.
Laboratory rats have been used for many decades to test drugs. In addition, much of what we know about cancer-causing molecules was learned through basic research with rats.
Mice can be genetically engineered to serve as models of Lou Gehrig's disease and many other human illnesses.
Insects such as fruit flies and honeybees are important models for learning how genes and the environment interact to affect behavior.
Studies with fruit flies, bread mold, bacteria and mice have defined the basic rules of circadian clocks, which drive daily biological rhythms, and revealed connections between these clocks and sleep deprivation, obesity, diabetes, depression and other human health conditions.
Research in worms has yielded important information about aging. This research is very difficult to do in people and other organisms that have long life spans.
Model organism research has produced many powerful tools used by scientists all over the world. Examples include RNA interference, DNA chips and genome-wide scanning methods. These tools are now being used in human health studies.
What more can model organism research tell us?
Scientists still do not have a good understanding of biological complexity, in which many molecular networks operate in synchrony inside our bodies. Researchers are mapping these networks in bacteria, yeast and other model organisms, and those studies will be instructive for creating working models of how cells, organs and tissues function in people.
Model organisms can also help reveal changes at the molecular level that are associated with diseases and identify diseases that are related to one another even though they initially may not appear to be. If there is already a drug to treat one of the diseases, scientists can then explore whether it might work for the related ones, as well.
These are the representative model organisms
1. Viruses
Phage lambda / Phi X 174 / SV40 / T4 Phage / Tobacco mosaic virus / Herpes simplex virus
2. Prokaryotes
Bacillus subtilis / E.coli / Caulobacter crescentus / Mycoplasma genitalium / Aliivibrio fischeri / Synechocytis / Psedomonas fluorescens
3. Eukaryotes
3 - 1. Protists
Chlamydomonas reinhardtii / Dictyostelium discoideum / Tetrahymena thermophila / Emiliania huxleyi / Thalassiosira pseudonana
3 - 2. Fungi
Ashbya gossypii / Aspergillus nidulans / Coprinus cinereus / Cryptococcus neoformans / Neurospora crassa / Saccharomyces cerevisiae / Schizophyllum commune / Schizosaccharomyces pombe / Ustilago maydis
3 - 3. Plants
Arabidopsis thaliana / The genus Boechera / Selaginella moellendorffii / Brachypodium distachyon / Setaria viridis / Lotus japonicus / Lemna gibba / Maize / Medicago truncatula / Mimulus guttatus / Nicotiana benthamiana / Tobacco BY-2 cells / Rice / Physcomitrella patens / Marchantia polymorpha / Populus
3 - 4. Animals
3 - 4. 1 Invertebrates
Caenorhabditis elegans / Amphimedon queenslandica / Arbacia punctulata / Aplysia / Branchiostoma floridae / Caledia captiva / Callosobruchus maculatus / Chorthippus parallelus / Ciona intestinalis / Daphnia spp / Coelopidae / Diopsidae / Drosophila / Euprymna scolopes / Galleria mellonella / Gryllus bimaculatus, / Hydra / Loligo pealei / Macrostomum lignano / Mnemiopsis leidyi / Nematostella vectensis / Oikopleura dioica / Oscarella carmela / Parhyale hawaiensis / Platynereis dumerilii / Podisma spp / Pristionchus pacificus /Scathophaga stercoraria / Schmidtea mediterranea / Stomatogastric ganglion / Strongylocentrotus purpuratus / Symsagittifera roscoffensis / Tribolium castaneum / Trichoplax adhaerens / Tubifex tubifex
3 - 4. 2 Vertebrates
Laboratory mice / Bombina bombina / Bombina variegata / Carolina anole (Anolis carolinensis) / Cat (Felis sylvestris catus) / Chicken (Gallus gallus domesticus) / Cotton rat (Sigmodon hispidus) / Dog (Canis lupus familiaris) / Golden hamster (Mesocricetus auratus) / Guinea pig (Cavia porcellus) / Little brown bat (Myotis lucifugus) / Medaka (Oryzias latipes, or Japanese ricefish) / Mouse (Mus musculus) / Naked mole-rat, (Heterocephalus glaber) / Pigeon (Columba livia domestica) / Poecilia reticulata / Rat (Rattus norvegicus) / rhesus monkey / Sea lamprey (Petromyzon marinus) / Takifugu (Takifugu rubripes, a pufferfish) / Three-spined stickleback (Gasterosteus aculeatus) / Xenopus tropicalis / Xenopus laevis / Zebra finch (Taeniopygia guttata) / Zebrafish (Danio rerio, a freshwater fish)
Current Models
Drosophila // Xenopus // Zebrafish // Mouse // C. elegans // Yeast // E. coli // Arabidopsis
References
1. https://en.wikipedia.org/wiki/Model_organism
2. https://en.wikipedia.org/wiki/List_of_model_organisms
3. https://www.nigms.nih.gov/Education/Pages/modelorg_factsheet.aspx
4. http://wormclassroom.org/teaching-model-organisms
