Introduction of C. elegans
——A model organism
Xiaoqi Sang
2011.6.10
Contents
A Short History
Characters of C.elegans
Applications of C. elegans
Nobel Prizes for C. elegans
C. elegans and Apoptosis
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Brief Introduction
whole name：Caenorhabditis elegans
Free-living, non-parasitic, transparent，
about 1 mm in length，lives in
temperate soil environments
Research into the molecular begun in
1974
Extensively used as a model organism
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A Short History
 In 1963, Sydney Brenner
introduced C. elegans as a
model organism for pursuing
research in developmental
biology and neurology
 In 1974, Brenner founded
that EMS can induction
specificity gene mutation of
C. elegans
 Now is widely used in
laboratory research
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Characters of C. elegans
 small (about 1 mm in length)
 Feeds on bacteria
 Easily to housed and cultivated in large numbers
 Transparent
 Easily to manipulation and observation
 Life cycle is short
 Have 1090 somatic cells at most
 Easily to mutagism
 Can be long-term storage
 Genome is completely sequenced
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C. elegans
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C. elegans
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Life Cycle
 From egg to egg
takes about 3 days
Life span is
around 2 to 3 weeks
under suitable
living condition
Once lay
approximately 3001000 eggs
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Life Cycle
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Genome
 The genome was completely sequenced in 1998, It is
the first multicellular-organism (animal) that has a
completely sequenced genome
 The genome size of C. elegans is about a hundred
million base pairs
 Five pairs of autosomes and one pair of sex
chromosome
 Contains approximately 20,100 protein-coding genes
 Contain more than 16,000 RNA genes
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Sexual determination
 C. elegans has two sexes: hermaphrodites and
males
 In nature, hermaphrodites are the most common sex,
just 0.05% is males
 Hermaphrodites can self-fertilize or mate with males
but cannot fertilize each other
 sex determined by the ratio of sex chromosome
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XX
hermaphrodite
XO
male
Applications of C. elegans
 Cellular differentiation
 Nervous system
 Embryo development
 Cell cycle
 Meiosis
 Fertilization
 Cleavage
 Fat metabolize
 RNA Interference (RNAi)
 Study and memory
 Aging
 Apoptosis
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Nobel Prizes for C. elegans!
 The first C. elegans Nobel Prize——The Nobel Prize in
Physiology or Medicine 2002
For the dicovery of Apoptosis
To Sydney Brenner, H. Robert Horvitz and John E. Sulston
 A second C. elegans Nobel Prize——The Nobel Prize in
Physiology or Medicine 2006
For the discovery of RNA interference - gene silencing by
double-stranded RNA
To Andrew Z. Fire and Craig C. Mello
 A third C. elegans Nobel Prize——The Nobel Prize in Chemistry
2008
For the discovery and development of the green fluorescent
protein
To Osamu Shimomura, Martin Chalfie and Roger Y. Tsien
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C. elegans and Apoptosis
 C. elegans hermaphrodites have 1090
somatic cells
 Mature C. elegans remains 959 cells
 131 cells commit suicide by apoptosis
 116 of the 131 dying cells are cells of the
nervous system and other ectoderm
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To be continue
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