Fig. S2.

Stable, mixed chimeras exhibit synchronized cycles of death and regeneration. Histocompatible, but genetically distinct, juvenile colonies were brought together in controlled allorecognition reactions (arrow indicates anastomotic blood vessel) and imaged in the postfusion period at 48-h intervals. Colonies grow through weekly cycles of development termed blastogenesis. New buds emerge (yellow, dotted outlines) from the body wall of each parental zooid. Chimeric partners exhibit developmental synchrony with each other. (Scale bars: 2 mm.)