Letter | Published:

Regulatory constraints in the evolution of the tetrapod limb anterior–posterior polarity

Nature volume 443, pages 985988 (26 October 2006) | Download Citation



The anterior to posterior (A–P) polarity of the tetrapod limb is determined by the confined expression of Sonic hedgehog (Shh) at the posterior margin of developing early limb buds1,2, under the control of HOX proteins encoded by gene members of both the HoxA and HoxD clusters3,4,5,6. Here, we use a set of partial deletions to show that only the last four Hox paralogy groups can elicit this response: that is, precisely those genes whose expression is excluded from most anterior limb bud cells owing to their collinear transcriptional activation. We propose that the limb A–P polarity is produced as a collateral effect of Hox gene collinearity, a process highly constrained by its crucial importance during trunk development. In this view, the co-option of the trunk collinear mechanism, along with the emergence of limbs, imposed an A–P polarity to these structures as the most parsimonious solution. This in turn further contributed to stabilize the architecture and operational mode of this genetic system.

Access optionsAccess options

Rent or Buy article

Get time limited or full article access on ReadCube.


All prices are NET prices.


  1. 1.

    & Ectodermal-Mesodermal Interaction in the Origin of Limb Symmetry 78–97 (Williams and Wilkins, Baltimore, 1968)

  2. 2.

    , , & Sonic hedgehog mediates the polarizing activity of the ZPA. Cell 75, 1401–1416 (1993)

  3. 3.

    et al. Hoxd-12 differentially affects preaxial and postaxial chondrogenic branches in the limb and regulates Sonic hedgehog in a positive feedback loop. Development 124, 4523–4536 (1997)

  4. 4.

    , , & Ectopic expression of Hoxb-8 causes duplication of the ZPA in the forelimb and homeotic transformation of axial structures. Cell 78, 589–601 (1994)

  5. 5.

    , & A dual role for Hox genes in limb anterior-posterior asymmetry. Science 304, 1669–1672 (2004)

  6. 6.

    et al. Pbx1/Pbx2 requirement for distal limb patterning is mediated by the hierarchical control of Hox gene spatial distribution and Shh expression. Development 133, 2263–2273 (2006)

  7. 7.

    , , , & Sonic hedgehog and Fgf-4 act through a signaling cascade and feedback loop to integrate growth and patterning of the developing limb bud. Cell 79, 993–1003 (1994)

  8. 8.

    , , & A positive feedback loop coordinates growth and patterning in the vertebrate limb. Nature 371, 609–612 (1994)

  9. 9.

    , , & Signal relay by BMP antagonism controls the SHH/FGF4 feedback loop in vertebrate limb buds. Nature 401, 598–602 (1999)

  10. 10.

    et al. Conditional inactivation of Fgf4 reveals complexity of signalling during limb bud development. Nature Genet. 25, 83–86 (2000)

  11. 11.

    , , , & Gremlin is the BMP antagonist required for maintenance of Shh and Fgf signals during limb patterning. Nature Genet. 34, 303–307 (2003)

  12. 12.

    , , & The limb bud Shh-Fgf feedback loop is terminated by expansion of former ZPA cells. Science 305, 396–399 (2004)

  13. 13.

    et al. Manifestation of the limb prepattern: limb development in the absence of Sonic hedgehog function. Dev. Biol. 236, 421–435 (2001)

  14. 14.

    , & Some distal limb structures develop in mice lacking Sonic hedgehog signaling. Mech. Dev. 100, 45–58 (2001)

  15. 15.

    et al. Cholesterol modification of Sonic hedgehog is required for long-range signaling activity and effective modulation of signaling by Ptc1. Cell 105, 599–612 (2001)

  16. 16.

    et al. Evidence for an expansion-based temporal Shh gradient in specifying vertebrate digit identities. Cell 118, 517–528 (2004)

  17. 17.

    et al. Early developmental arrest of mammalian limbs lacking HoxA/HoxD gene function. Nature 435, 1113–1116 (2005)

  18. 18.

    & Control of Hoxd genes' collinearity during early limb development. Dev. Cell 10, 93–103 (2006)

  19. 19.

    , & Fossils, genes and the evolution of animal limbs. Nature 388, 639–648 (1997)

  20. 20.

    et al. Specific and redundant functions of the paralogous Hoxa-9 and Hoxd-9 genes in forelimb and axial skeleton patterning. Development 122, 461–472 (1996)

  21. 21.

    et al. Murine genes related to the Drosophila AbdB homeotic gene are sequentially expressed during development of the posterior part of the body.. EMBO J. 10, 2279–2289 (1991)

  22. 22.

    , & Gene transpositions in the HoxD complex reveal a hierarchy of regulatory controls. Cell 85, 1025–1035 (1996)

  23. 23.

    The origin of vertebrate limbs. Development (Suppl.) 120, 169–180 (1994)

  24. 24.

    , , , & Mechanisms of Hox gene colinearity: transposition of the anterior Hoxb1 gene into the posterior HoxD complex. Genes Dev. 14, 198–211 (2000)

  25. 25.

    , , & HoxD cluster scanning deletions identify multiple defects leading to paralysis in the mouse mutant Ironside. Genes Dev. 19, 2862–2876 (2005)

  26. 26.

    et al. Sonic hedgehog, a member of a family of putative signaling molecules, is implicated in the regulation of CNS polarity. Cell 75, 1417–1430 (1993)

  27. 27.

    Differential staining of cartilage and bone in fetal mouse skeleton by alcian blue and alizarin red. Congenital Anomalies 16, 171–173 (1976)

Download references


We thank N. Fraudeau and T. H. N. Huynh for technical assistance as well as C. Tabin and M. Coates for comments and suggestions. This work was supported by funds from the canton de Genève, the Louis-Jeantet foundation, the Swiss National Research Fund, the National Center for Competence in Research (NCCR) ‘Frontiers in Genetics’ and the EU programme ‘Cells into Organs’.

Author information

Author notes

    • Basile Tarchini
    •  & Marie Kmita

    Present addresses: Department of Biology, McGill University, 1205 Avenue Docteur Penfield, Montreal H3A 1B1, Quebec, Canada (B.T.); Laboratory of Genetics and Development, Institut de Recherches Cliniques de Montréal (IRCM), Université de Montréal, 110 avenue des Pins Ouest, H2W 1R7, Montréal, Quebec, Canada (M.K.)


  1. Department of Zoology and Animal Biology and National Research Centre ‘Frontiers in Genetics’, University of Geneva, Sciences III, Quai Ernest Ansermet 30, 1211 Geneva 4, Switzerland

    • Basile Tarchini
    • , Denis Duboule
    •  & Marie Kmita


  1. Search for Basile Tarchini in:

  2. Search for Denis Duboule in:

  3. Search for Marie Kmita in:

Competing interests

Reprints and permissions information is available at www.nature.com/reprints. The authors declare no competing financial interests.

Corresponding author

Correspondence to Denis Duboule.

About this article

Publication history






Further reading


By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.