Introduction of C. elegans ——A model organism Xiaoqi Sang

Page  2 Contents A Short History Characters of C.elegans Nobel Prizes for C. elegans C. elegans and Apoptosis Applications of C. elegans

Page  3 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

Page  4 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

Page  5 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 Nice model organism!

Page  6 C. elegans

Page  7 C. elegans

Page  8 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 eggs

Page  9 Life Cycle

Page  10 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

Page  11 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 XX hermaphrodite XO male

Page  12 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

Page  13 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

Page  14 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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