Par en May 2017
Macrostomum lignano, a new model for studying the biology of flatworms
Macrostomum lignano (wikipedia) is an emerging invertebrate model that possesses many advantages over the classical worm models such as Caenorhabditis elegans (nematodes), Schmidtea mediterranea or Dugesia japonica (Planaria). In particular, this platyhelminth is extensively studied for its regeneration properties in order to address fundamental questions regarding stem cell biology, regeneration, and aging.   
Bright field image of Macrostomum lignano.
For example, an amputated head regenerates the posterior part within 10 days but a posterior part of M. lignano does not regenerate a new head. A single individual has been shown to regenerate the posterior part over 59 consecutive amputations.  Worms are also extremely resistant to irradiation and can tolerate up to 200Gy.   In addition, adult worms show a high plasticity. Starvation for up to three months leads to “degrowth” and animals acquire the morphology of hatchlings. After restauration of feeding, all tissues and organs will restore giving heathy adults. 
All these regenerative properties are due to the presence of numerous stem cells (1600 of 25000 total cells, also called neoblasts). These neoblasts are thought to be totipotent and can give rise to all cell types including the gonads. 
Full genome sequencing, transcriptome and annotation have been initiated at the Hubrecht Institute (E. Berezikov) and are currently carried out by an informal consortium of several research groups. (http://www.macgenome.org/genome.html)