During the last stage of a typical blastogenic cycle (the takeover stage), all zooids in a colony regress over a 24- to 30-h period through the death of all visceral tissues, primarily by apoptosis (Lauzon et al., 1992, 1993).
These changes often led to the death of previously separated ramets from a given genet simultaneously within the same blastogenic cycle.
Life span was recorded as number of blastogenic cycles until death.
As illustrated in Figure 1, death was synchronous between all ramets in 7 of 11 colonies (Y8, 275jjr, 403d, 386i, 433z, 435h, 360c), occurring within the same blastogenic cycle.
schlosseri pair genets was performed during developmental stages A-C of the blastogenic cycle (described in Milkman, 1967).
Transplantations were also done at different points of the blastogenic cycle (Milkman, 1967) to test for any variability in the alloresponse.
Any variations in the time scale of resorption (2-5 days) were related to the blastogenic cycle.
Where partial resorption was recorded [ILLUSTRATION FOR FIGURE 1f OMITTED], the leftover parts remained within the tunic for the whole blastogenic cycle and were completely resorbed only during the takeover stage.
Observations on the contact sites and colonies were made under the dissecting microscope at least once a week to confirm the location of "each partner" in the chimera in accordance with the developing buds during successive blastogenic
Furthermore, both transcripts were expressed during all stages of the blastogenic cycle in Botryllus ([ILLUSTRATION FOR FIGURE 4 OMITTED], panel B).
Samples (0.2 [[micro]gram]) of Poly-[A.sup.+] RNA from various developmental stages were translated with a rabbit reticulocyte lysate with 35S-methionine and analyzed by two-dimensional polyacrylamide gel electrophoresis to examine patterns of gene expression between different stages of the blastogenic cycle.
First, although both transcripts were expressed at all phases of the blastogenic cycle in Botryllus including takeover, the relative intensity of the bands varied at different stages of the cycle.