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Developmental origins of precocial forelimbs in marsupial neonates.

dc.contributor.author Keyte, Anna L
dc.contributor.author Smith, Kathleen K
dc.coverage.spatial England
dc.date.accessioned 2011-06-21T17:27:31Z
dc.date.issued 2010-12
dc.identifier http://www.ncbi.nlm.nih.gov/pubmed/21098569
dc.identifier 137/24/4283
dc.identifier.uri https://hdl.handle.net/10161/4175
dc.description.abstract Marsupial mammals are born in an embryonic state, as compared with their eutherian counterparts, yet certain features are accelerated. The most conspicuous of these features are the precocial forelimbs, which the newborns use to climb unaided from the opening of the birth canal to the teat. The developmental mechanisms that produce this acceleration are unknown. Here we show that heterochronic and heterotopic changes early in limb development contribute to forelimb acceleration. Using Tbx5 and Tbx4 as fore- and hindlimb field markers, respectively, we have found that, compared with mouse, both limb fields arise notably early during opossum development. Patterning of the forelimb buds is also accelerated, as Shh expression appears early relative to the outgrowth of the bud itself. In addition, the forelimb fields and forelimb myocyte allocation are increased in size and number, respectively, and migration of the spinal nerves into the forelimb bud has been modified. This shift in the extent of the forelimb field is accompanied by shifts in Hox gene expression along the anterior-posterior axis. Furthermore, we found that both fore- and hindlimb fields arise gradually during gastrulation and extension of the embryonic axis, in contrast to the appearance of the limb fields in their entirety in all other known cases. Our results show a surprising evolutionary flexibility in the early limb development program of amniotes and rule out the induction of the limb fields by mature structures such as the somites or mesonephros.
dc.language eng
dc.language.iso en_US
dc.publisher The Company of Biologists
dc.relation.ispartof Development
dc.relation.isversionof 10.1242/dev.049445
dc.subject Animals
dc.subject Animals, Newborn
dc.subject Forelimb
dc.subject Hedgehog Proteins
dc.subject Immunohistochemistry
dc.subject Marsupialia
dc.title Developmental origins of precocial forelimbs in marsupial neonates.
dc.title.alternative
dc.type Journal article
duke.contributor.id Smith, Kathleen K|0117176
dc.description.version Version of Record
duke.date.pubdate 2010-12-15
duke.description.issue 24
duke.description.volume 137
dc.relation.journal Development
pubs.author-url http://www.ncbi.nlm.nih.gov/pubmed/21098569
pubs.begin-page 4283
pubs.end-page 4294
pubs.issue 24
pubs.organisational-group Biology
pubs.organisational-group Duke
pubs.organisational-group Trinity College of Arts & Sciences
pubs.publication-status Published
pubs.volume 137
dc.identifier.eissn 1477-9129


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