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1982 (1)
1Author    Rainer Gilles, Lothar JaenickeRequires cookie*
 Title    Differentiation in Volvox carteri: Study of Pattern Variation of Reproductive Cells  
 Abstract    Asexual spheroids of the multicellular green alga Volvox are composed o f two types o f cells: non-flagellated reproductive gonidia and Chlamydomonas-\ike flagellated somatic cells. They are committed by a differentiating cleavage during embryogenesis. The gonidia o f the adult spheroids form a symmetrical pattern consisting o f four layers o f four gonidia each; their position is established already in the embryos by the gonidial initials. Whereas, generally, the 16-gonidia pattern is assumed to be the basic one, most o f the spheroids have fewer gonidia (down to 8). The nine possible gonidial patterns (8 to 16 gonidia) are described and correlated to the gonidial stem cells which have been differentiated. Defects in gonidial pattern are o f particular interest, since any model of differentiation has to explain not only the basic pattern formed, but also its systematic variations. Our study shows that the pattern reduction is by no means random, but governed by an intrinsic mechanism which shifts the first unequal cleavage from the 32-celled stage to the 16-celled stage. All the patterns formed can be deduced from cleavage pathways involving non-synchronous differentiation of the stem cells. Thus, pattern formation can be correlated to timing and spacing signals regulating events during embryogenesis. 
  Reference    Z. Naturforsch. 37c, 1023—1030 (1982); received June 1 1982 
  Published    1982 
  Keywords    Volvox carteri, Differentiation, Embryogenesis, Cell Lineages, Pattern Formation 
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 TEI-XML for    default:Reihe_C/37/ZNC-1982-37c-1023.pdf 
 Identifier    ZNC-1982-37c-1023 
 Volume    37