Heterochrony in the regulation of the developing marsupial limb. Issue 2 (13th November 2013)

• Record Type: Journal Article
• Authors: Chew, Keng Yih; Shaw, Geoffrey; Yu, Hongshi; Pask, Andrew J.; Renfree, Marilyn B.
• Is Part Of: Developmental dynamics. Volume 243:Issue 2(2014:Feb.)
• Page Start: 324
• Page End: 338
• Publication Date: 2013-11-13
• Subjects: Morphogenesis -- Periodicals; Anatomy -- Periodicals; Anatomie -- Périodiques; Biologie du développement -- Périodiques; 571.833
• DOI: 10.1002/dvdy.24062
• Languages: English
• ISSNs: 1058-8388

Abstract

<abstract abstract-type="main"> <title>ABSTRACT</title> <sec id="dvdy24062-sec-0001" sec-type="section"> <p> <underline>Background</underline>: At birth, marsupial neonates have precociously developed forelimbs. The development of the tammar wallaby (<italic>Macropus eugenii</italic>) hindlimbs lags significantly behind that of the forelimbs. This differs from the grey short‐tailed opossum, <italic>Monodelphis domestica</italic>, which has relatively similar fore‐ and hindlimbs at birth. This study examines the expression of the key patterning genes <italic>TBX4, TBX5, PITX1, FGF8</italic>, and <italic>SHH</italic> in developing limb buds in the tammar wallaby. <underline>Results</underline>: All genes examined were highly conserved with orthologues from opossum and mouse. <italic>TBX4</italic> expression appeared earlier in development than in the mouse, but later than in the opossum. <italic>SHH</italic> expression is restricted to the zone of polarising activity, while <italic>TBX5</italic> (forelimb) and <italic>PITX1</italic> (hindlimb) showed diffuse mRNA expression. <italic>FGF8</italic> is specifically localised to the apical ectodermal ridge, which is more prominent than in the opossum. <underline>Conclusions</underline>: The most marked divergence in limb size in marsupials occurs in the kangaroos and wallabies. The faster development of the fore limb compared to that of the hind limb correlates with the early timing of the expression of the key patterning genes in these limbs. <italic>Developmental Dynamics 243:324–338, 2014</italic>. © 2013 Wiley Periodicals, Inc.</p> </sec> </abstract>