TY  - JOUR
TI  - Variation in spiralian development: insights from polychaetes
AU  - Seaver, ElaineC.
T2  - The International Journal of Developmental Biology
AB  - Spiralian development is characterized by the conservation of spindle orientation and cell geometry during early cleavage stages, as well as features of the ultimate fates of identified cells. This complex set of characters is shared by a number of animal lineages including nemerteans, polyclad platyhelminthes, annelids and mollusks. How a similar, highly stereotypical cleavage program can give rise to such diversity of larval and adult forms has intrigued researchers for many years. This review summarizes recent data from polychaete annelids, and highlights both conservation and variation in the cellular and molecular mechanisms that guide the spiral cleavage developmental program. There is a specific focus on comparisons of fate maps, patterns of cleavage, mechanisms of cell fate specification, organizing activity, and differences in molecular patterning. Some of the differences in early development represent intra-clade variation within annelids, and others hint at differences between annelids and other taxa. Because much of the classic work on spiralians has focused on mollusks, these new data from annelids have expanded our knowledge about the evolutionary flexibility in spiralian development and potentially its role in body plan evolution. 
PY  - 2014
DO  - 10.1387/ijdb.140154es
VL  - 58
IS  - 6-7-8
SP  - 457
EP  - 467
J2  - Int. J. Dev. Biol.
LA  - en
SN  - 0214-6282
SN  - 1696-3547
UR  - https://ijdb.ehu.eus/article/140154es
Y2  - 2024/11/23/14:00:03
ER  -