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Developmental origins of precocial forelimbs in marsupial neonates.

Publication ,  Journal Article
Keyte, AL; Smith, KK
Published in: Development (Cambridge, England)
December 2010

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.

Duke Scholars

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Published In

Development (Cambridge, England)

DOI

EISSN

1477-9129

ISSN

0950-1991

Publication Date

December 2010

Volume

137

Issue

24

Start / End Page

4283 / 4294

Related Subject Headings

  • Marsupialia
  • Immunohistochemistry
  • Hedgehog Proteins
  • Forelimb
  • Animals, Newborn
  • Animals
  • 42 Health sciences
  • 32 Biomedical and clinical sciences
  • 31 Biological sciences
  • 11 Medical and Health Sciences
 

Citation

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Keyte, A. L., & Smith, K. K. (2010). Developmental origins of precocial forelimbs in marsupial neonates. Development (Cambridge, England), 137(24), 4283–4294. https://doi.org/10.1242/dev.049445
Keyte, Anna L., and Kathleen K. Smith. “Developmental origins of precocial forelimbs in marsupial neonates.Development (Cambridge, England) 137, no. 24 (December 2010): 4283–94. https://doi.org/10.1242/dev.049445.
Keyte AL, Smith KK. Developmental origins of precocial forelimbs in marsupial neonates. Development (Cambridge, England). 2010 Dec;137(24):4283–94.
Keyte, Anna L., and Kathleen K. Smith. “Developmental origins of precocial forelimbs in marsupial neonates.Development (Cambridge, England), vol. 137, no. 24, Dec. 2010, pp. 4283–94. Epmc, doi:10.1242/dev.049445.
Keyte AL, Smith KK. Developmental origins of precocial forelimbs in marsupial neonates. Development (Cambridge, England). 2010 Dec;137(24):4283–4294.
Journal cover image

Published In

Development (Cambridge, England)

DOI

EISSN

1477-9129

ISSN

0950-1991

Publication Date

December 2010

Volume

137

Issue

24

Start / End Page

4283 / 4294

Related Subject Headings

  • Marsupialia
  • Immunohistochemistry
  • Hedgehog Proteins
  • Forelimb
  • Animals, Newborn
  • Animals
  • 42 Health sciences
  • 32 Biomedical and clinical sciences
  • 31 Biological sciences
  • 11 Medical and Health Sciences