Determination of cleavage pattern in embryonic blast cells of the leech.
The o blast cells of the leech embryo become committed to one of two alternative cleavage geometries shortly before they divide. Cleavage geometry depends upon the presence or absence of the adjoining p bandlet, and if that bandlet is ablated, the pattern of o blast cell cleavages will undergo an abrupt transition several hours later. Previous work has shown that the oblast cell becomes committed to the formation of a particular complement of postmitotic descendants early in its differentiation, but the present findings suggest that cleavage pattern and descendant fate are determined at separate commitment events.
D000818:Animals; D001757:Blastomeres / Q000166:cytology*; D002455:Cell Division; D007865:Leeches / Q000196:embryology*