Although unusual among animals in general, a neoblast
stem cell system is also known from a group of small,
soft-bodied marine worms known as acoels. In a recent
study published in BMC Developmental Biology, De
Mulder et al. [4] present the first detailed characterization
of this stem cell system in acoels. Working with the acoel
Isodiametra pulchra, De Mulder et al. investigated
neoblast distribution and proliferation using
morphological analyses and S-phase cell labelling and
also characterized in these animals the expression and
function of a conserved stem-cell regulator.