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Fig. 1. Cell lineage of endoderm in the ascidian. (A) Positions of the anterior
(orange) and posterior (yellow) endoderm and their precursor blastomeres.
Eight-cell embryo is lateral view. Anterior is towards the left, animal pole
is upwards. Sixty-four-cell embryo is vegetal view. Anterior is upwards. (B)
Lineage tree starting from B4.1 posterior-vegetal blastomeres of an eight-cell
embryo. Endoderm lineage is yellow. Minor fates are indicated in
parentheses.