MODEL ORGANISMS Flashcards
A non-human species that is extensively studied to understand basic biological phenomena, with the expectation that discoveries made in the model organism can be extrapolated to other species, including humans
MODEL ORGANISM
The foundations of molecular biology were based on studies of
BACTERIA
Eukaryotic system.
Signaling molecules and cell cycle are nearly similar.
Good model system to understand many human diseases including
cancer
Ease of genetic manipulation allows its use for analyzing and
functionally dissecting gene products from other eukaryotes
Last decade four Nobel prizes were awarded for discoveries involving
YEAST
One of the best characterized multicellular nematode at the level of genomics, genetics, and embryology
Genome is fully sequenced
Unique in that it can be grown and genetically manipulated with the speed and ease of a micro-organism while offering the features of a real animal
has a full set of organ systems, has complex sensory systems, shows coordinated behavior, and it is possible to trace the lineage of every one of its approximately 1000 constituent cells
CAENORHABDITIS ELEGANS
A versatile model organism that has been used extensively for
biomedical research.
Easy-to-manipulate genetic system and can be used to study
development, physiology and behavior.
Biological complexity comparable to that of a mammal
Many organ systems in mammals have well-conserved homologous in Drosophila
Has provided new insights into forms of cancer,
neurodegenerative diseases, behavior, immunity, aging, multigenic inheritance, and development.
FRUIT FLY (DROSOPHILA)
Small size, short life cycle, ease of culture, and ability to readily produce mutations relevant to human health and disease
The embryonic development can be seen through its transparent
egg and closely resembles that of higher vertebrates
Other shared features with humans include blood, kidney, and
optical systems
In addition, its genome is half the size of the mouse and human
genomes, which is valuable in identification of key vertebrate genes.
Development in ex vivo.
Entire initial development is transparent.
48hrs is enough for the development of most of the organ systems.
DANIO RERIO
provides an excellent model system for studying the development of higher vertebrates wherein growth accompanies morphogenesis
CHICK EMBRYO
Closest mammalian model organism to humans
Genes that code for proteins responsible for carrying out vital
biological processes in both the human and the mouse share a high degree of similarity.
Therefore, the mouse has already proven extremely useful in
development, genetic, and immunology studies
A great system for studying and understanding human disease, as well as a mechanism for investigating new treatment strategies in ways that cannot be done in humans
MUS MUSCULUS (MOUSE)
Small flowering plant
Has a small genome relative to other plants and is easily grown under laboratory conditions
Amenable to some genetics particularly generation of transgenics
Allows insight into numerous features of plant biology, including those of significant value to agriculture, energy, environment, and human health
ARABIDOPSIS THALIANA (THALE CRESS)
ADVANTAGES:
- Genome sequenced
- Excellent genetics
- RNAi effective
- Fast generation time
- Second site suppressor/enhancer screens
- Powerful molecular techniques
- Genes can be easily cloned
- Transgenic animals easily generated
- Targeted misexpression of genes in space and time
- Mosaic analysis: determine where gene acts
- Laser ablation of single cells possible
LIMITATIONS:
- Embryological manipulations difficult
- Targeted gene disruption still difficult although possible
FRUIT FLY (DROSOPHILA)
ADVANTAGES:
- Simplest vertebrate
- Good genetics
- Transparent embryos
- Embryo manipulations possible
- Organ system similar to other vertebrates (e.g., eyes, heart, blood, gastrointestinal tract)
- Rapid vertebrate development
LIMITATIONS:
- Not yet trivial to clone genes
- Transgenics not trivial
- Not targeted gene disruption
ZEBRA FISH
ADVANTAGES:
- Excellent genetics
- Genes can be easily cloned
- Powerful molecular techniques
- Possess all basic eukaryotic cell organelles
- Cell cycle control similar to animals
LIMITATIONS:
- Unicellular
- No distinct tissues
YEAST
ADVANTAGES:
- Excellent genetics
- Hermaphrodites/self-fertilization
- Fast generation times
- Powerful molecular techniques
(cloning, RNAi)
- Genome sequence complete
- Few cells: 959 cells and lineages known
- Morphology fully characterized
LIMITATIONS:
- Limited external morphology
- Less similar to human
- Some embryological manipulations difficult
CAENORHABDITIS ELEGANS
ADVANTAGES:
- Universal model plant
- Small size
- Relatively short life cycle
- Small, sequenced genome
- Transformed easily
- Transgenics
LIMITATIONS:
- Embryological manipulations non-trivial
THALE CRESS
ADVANTAGES:
- Availability, low cost
- Accessibility, outside of mother
- Great for embryological manipulation; transplants of tissue
- Easily transfected by avian retroviruses
LIMITATIONS:
- Limited genetics
- Genome sequenced
CHICK/ CHICK EMBRYO
