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Limb positioning and initiation: An evolutionary context of pattern and formation
Author(s) -
Royle Samantha R.,
Tabin Clifford J.,
Young John J.
Publication year - 2021
Publication title -
developmental dynamics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.634
H-Index - 141
eISSN - 1097-0177
pISSN - 1058-8388
DOI - 10.1002/dvdy.308
Subject(s) - biology , limb bud , limb development , amniote , zone of polarizing activity , context (archaeology) , evolutionary biology , anatomy , mesoderm , lower limb , evolutionary developmental biology , scope (computer science) , limb loss , vertebrate , paleontology , embryo , embryonic stem cell , computer science , genetics , gene , amputation , medicine , psychology , surgery , psychiatry , programming language
Before limbs or fins, can be patterned and grow they must be initiated. Initiation of the limb first involves designating a portion of lateral plate mesoderm along the flank as the site of the future limb. Following specification, a myriad of cellular and molecular events interact to generate a bud that will grow and form the limb. The past three decades has provided a wealth of understanding on how those events generate the limb bud and how variations in them result in different limb forms. Comparatively, much less attention has been given to the earliest steps of limb formation and what impacts altering the position and initiation of the limb have had on evolution. Here, we first review the processes and pathways involved in these two phases of limb initiation, as determined from amniote model systems. We then broaden our scope to examine how variation in the limb initiation module has contributed to biological diversity in amniotes. Finally, we review what is known about limb initiation in fish and amphibians, and consider what mechanisms are conserved across vertebrates.