model organisms.pptx

1. Biologists use model organisms
• Model organisms are species used to study and
understand biological processes
• They are easy to maintain and breed in
laboratory setup
• Usually have short life span and breed in large
numbers
• some model organisms are selected because of
their pivotal position in the evolutionary tree
• Model organisms can be used to create highly
detailed genetic map

2. E.coli
• Escherichia coli is a gram negative rod shaped
bacteria
• Commonly found in GI tract of warm blooded
animals
• Have a small genome 4.5 – 5.5 mbp
• They reproduce very rapidly doubling their
population every 20 minutes
• They can be manipulated and engineered easily
• Currently they are widely used as a vector or for
synthesis of protein of interest

3. S. Cerevisiae (Brewer’s yeast)
• S. cerevisiae is a single celled eukaryote
belonging to kingdom fungi
• Lives primarily on fruits, flowers, and other sugar
containing substrates
• Their genome have 16 chromosomes
• They also have extra nuclear genomes
• Ferments glucose to ethanol and carbon dioxide
• Widely used in agriculture, pharmaceuticals,
environmental industries for biocatalysis

4. D. Melanogaster (fruit fly)
• Some of the most important discoveries in
genetics came from the study of Drosophila
e.g. – linkage, arrangement of genes on
chromosomes
• Contains only four chromosomes but more
than 15000 genes
• Many similar features and pathways with
humans
• Humans and drosophila have retained 60% of
the genes from their common ancestor

5. C. Elegans
• Free living transparent nematodes (roundworms)
lives in soil
• Organism is transparent and easy for
manipulation and observation
• One of the simplest organism with a nervous
system
• About 35% C. Elegans genes have human
homologs
• Used in the field of neurobiology and behavioral
genetics

6. Arabidopsis Thaliana
• Grows as weeds In many part of the world
• Has 5 sets of chromosomes
• Many variants are available
• 18% genes are common with human genomes
• Basic life processes are similar to more
complex crop plants
• Used in the study of gene regulation and
genetics of plant development

7. Mus Musculus (mouse)
• Share similarity with humans in terms of
anatomy, physiology and genetics
• There are over 3000 genetically defined
strains
• Approximately 40% of the human genomes
can be aligned to the mouse genomes
• Used to understand protein evolution in
mammals, ageing process in humans etc.