Autoreactive blood cells and programmed cell death in growth and development of protochordates
Allogeneic resorption in colonial protochordates of nonself recognition.
Heritable germ and somatic cell lineage competitions in chimeric colonial protochordates.
These results suggest that ancient invention of NC GRN likely occurred during the early Cambrian, within the estimated 200 million years of transition from protochordates
to vertebrates (Meulemans and Bronner-Fraser, 2005; Sauka-Spengler and Bronner-Fraser, 2006; Sauka-Spengler et al.
Taxa ranging from algae to higher plants, and from cnidarians to protochordates
, grow through the iterated replication of individual modules to form large, integrated individuals or colonies (Jackson et al.
Studies of fused allogeneic colonies of the protochordate Botryllus schlosseri have shown that the eggs of one partner may be retained and brooded by the other partner over several reproductive cycles (Sabbadin and Zaniolo, 1979).
This is the first demonstration in a protochordate that, under natural field conditions, allogeneic contacts leading to both fusion and rejection come at a cost to life-history processes such as growth and reproduction.
Protochordate allorecoghition is controlled by a MHC-like gene system.
Allorecoghition histocompatibility in a protochordate species: Is the relationship to MHC semantic or structural?
Harrimania planktophilus appears to have a feeding behavior similar to that described in protochordates
, suggesting that a filter-feeding pharynx evolved before the divergence of the hemichordate-echinoderm clade from the chordates.