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Developmental basis of limblessness and axial patterning in snakes

Abstract

The evolution of snakes involved major changes in vertebrate body plan organization, but the developmental basis of those changes is unknown. The python axial skeleton consists of hundreds of similar vertebrae, forelimbs are absent and hindlimbs are severely reduced. Combined limb loss and trunk elongation is found in many vertebrate taxa1, suggesting that these changes may be linked by a common developmental mechanism. Here we show that Hox gene expression domains are expanded along the body axis in python embryos, and that this can account for both the absence of forelimbs and the expansion of thoracic identity in the axial skeleton. Hindlimb buds are initiated, but apical-ridge and polarizing-region signalling pathways that are normally required for limb development are not activated. Leg bud outgrowth and signalling by Sonic hedgehog in pythons can be rescued by application of fibroblast growth factor or by recombination with chick apical ridge. The failure to activate these signalling pathways during normal python development may also stem from changes in Hox gene expression that occurred early in snake evolution.

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Figure 1: Morphology of python axial and appendicular skeleton.
Figure 2: Whole-mount antibody staining showing Hox gene expression in python and chick embryos.
Figure 3: Antibody staining and scanning electron micrographs comparing apical ectoderm in python and chick limb buds.
Figure 4: Polarizing activity and dorsoventral polarity in python hindlimb buds.
Figure 5: Developmental model for the evolution of snakes.

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References

  1. Carroll, R. Vertebrate Paleontology and Evolution(Freeman, New York, (1988).

    Google Scholar 

  2. Lee, M. S. Y. & Caldwell, M. W. Anatomy and relationships of Pachyrhachis problematicus, a primitive snake with hindlimbs. Phil. Trans. R. Soc. Lond. B 353, 1521–1552 (1998).

    Article  Google Scholar 

  3. Gaunt, S. J. Conservation in the Hox code during morphological evolution. Int. J. Dev. Biol. 38, 549–552 (1994).

    CAS  PubMed  Google Scholar 

  4. Burke, A. C., Nelson, C. E., Morgan, B. A. & Tabin, C. Hox genes and the evolution of vertebrate axial morphology. Development 121, 333–346 (1995).

    CAS  PubMed  Google Scholar 

  5. Cohn, M. J.et al. Hox9 genes and vertebrate limb specification. Nature 387, 97–101 (1997).

    Article  ADS  CAS  Google Scholar 

  6. Rancourt, D. E., Tsuzuki, T. & Capecchi, M. R. Genetic interaction between Hoxb-5 and Hoxb-6 is revealed by nonallelic noncomplementation. Genes Dev. 9, 108–122 (1995).

    Article  CAS  Google Scholar 

  7. Oliver, G., Wright, C. V., Hardwicke, J. & De Robertis, E. M. Differential antero-posterior expression of two proteins encoded by a homeobox gene in Xenopus and mouse embryos. EMBO J. 7, 3199–3209 (1988).

    Article  CAS  Google Scholar 

  8. Shashikant, C. S.et al. Regulation of Hoxc-8 during mouse embryonic development: identification and characterization of critical elements involved in early neural tube expression. Development 121, 4339–4347 (1995).

    CAS  PubMed  Google Scholar 

  9. Wall, N. A., Jones, C. M., Hogan, B. L. & Wright, C. V. Expression and modification of Hox 2.1 protein in mouse embryos. Mech. Dev. 37, 111–120 (1992).

    Article  CAS  Google Scholar 

  10. Oliver, G., De Robertis, E. M., Wolpert, L. & Tickle, C. Expression of a homeobox gene in the chick wing bud following application of retinoic acid and grafts of polarizing region tissue. EMBO J. 9, 3093–3099 (1990).

    Article  CAS  Google Scholar 

  11. Nelson, C. E.et al. Analysis of Hox gene expression in the chick limb bud. Development 122, 1449–1466 (1996).

    CAS  PubMed  Google Scholar 

  12. Saunders, J. W. The proximo-distal sequence of origin of the parts of the chick wing and the role of the ectoderm. J. Exp. Zool. 108, 363–402 (1948).

    Article  Google Scholar 

  13. Fang, H. & Elinson, R. P. Patterns of distal-less gene expression and inductive interactions in the head of the direct developing frog Eleutherodactylus coqui. Dev. Biol. 179, 160–172 (1996).

    Article  CAS  Google Scholar 

  14. Ferrari, D.et al. The expression pattern of the Distal-less homeobox-containing gene Dlx-5 in the developing chick limb bud suggests its involvement in apical ectodermal ridge activity, pattern formation, and cartilage differentiation. Mech. Dev. 52, 257–264 (1995).

    Article  CAS  Google Scholar 

  15. Savage, M. P.et al. Distribution of FGF-2 suggests it has a role in chick limb bud growth. Dev. Dyn. 198, 159–170 (1993).

    Article  CAS  Google Scholar 

  16. Davidson, D. R., Crawley, A., Hill, R. E. & Tickle, C. Position-dependent expression of two related homeobox genes in developing vertebrate limbs. Nature 352, 429–431 (1991).

    Article  ADS  CAS  Google Scholar 

  17. Niswander, L., Jeffrey, S., Martin, G. R. & Tickle, C. Apositive feedback loop coordinates growth and patterning in the vertebrate limb. Nature 371, 609–612 (1994).

    Article  ADS  CAS  Google Scholar 

  18. Laufer, E., Nelson, C. E., Johnson, R. L., Morgan, B. A. & Tabin, C. 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).

    Article  CAS  Google Scholar 

  19. Raynaud, A., Kan, P., Bouche, G. & Duprat, A. M. Fibroblast growth factors (FGF-2) and delayed involution of the posterior limbs of the slow-worm embryo (Anguis fragilis, L.). C. R. Acad. Sci. 318, 573–578 (1995).

    CAS  Google Scholar 

  20. Altabef, M., Clarke, J. D. W. & Tickle, C. Dorso-ventral ectodermal compartments and origin of apical ectodermal ridge in developing chick limb. Development 124, 4547–4546 (1997).

    CAS  PubMed  Google Scholar 

  21. Zeller, R. & Duboule, D. Dorso-ventral limb polarity and origin of the ridge: on the fringe of independence? BioEssays 19, 541–546 (1997).

    Article  CAS  Google Scholar 

  22. Davis, C. A., Holmyard, D. P., Millen, K. J. & Joyner, A. L. Examining pattern formation in mouse, chicken and frog embryos with an En-specific antiserum. Development 111, 287–298 (1991).

    CAS  PubMed  Google Scholar 

  23. Riddle, R. D.et al. Induction of LIM homeobox gene Lmx-1 by WNT7a establishes dorsoventral pattern in the vertebrate limb. Cell 83, 631–640 (1995).

    Article  CAS  Google Scholar 

  24. Chiang, C.et al. Cyclopia and defective axial patterning in mice lacking Sonic hedgehog gene function. Nature 383, 407–413 (1996).

    Article  ADS  CAS  Google Scholar 

  25. Marti, E., Takada, R., Bumcrot, D. A., Sasaki, H. & McMahon, A. P. Distribution of Sonic hedgehog peptides in the developing chick and mouse embryo. Development 121, 2537–2547 (1995).

    CAS  PubMed  Google Scholar 

  26. Marigo, V., Scott, M. P., Johnson, R. L., Goodrich, L. V. & Tabin, C. J. Conservation in hedgehog signaling: induction of a chicken patched homolog by Sonic hedgehog in the developing limb. Development 122, 1225–1233 (1996).

    CAS  PubMed  Google Scholar 

  27. Yang, Y.et al. Relationship between dose, distance and time in Sonic Hedgehog -mediated regulation of anteroposterior polarity in the chick limb. Development 124, 4393–4404 (1997).

    CAS  PubMed  Google Scholar 

  28. Charite, J., de Graaff, W., Shen, S. & Deschamps, J. Ectopic expression of Hoxb-8 causes duplication of the ZPA in the forelimb and homeotic transformation of axial structures. Cell 78, 589–601 (1994).

    Article  CAS  Google Scholar 

  29. Geduspan, J. S. & MacCabe, J. A. Transfer of dorsoventral information from mesoderm to ectoderm at the onset of limb development. Anat. Rec. 224, 79–87 (1989).

    Article  CAS  Google Scholar 

  30. Wilson, V. & Beddington, R. Expression of T protein in the primitive streak is necessary and sufficient for posterior mesoderm movement and somite differentiation. Dev. Biol. 192, 45–58 (1997).

    Article  CAS  Google Scholar 

  31. Panganiban, G., Sebring, A., Nagy, L. & Carroll, S. The development of crustacean limbs and the evolution of arthropods. Science 270, 1363–1366 (1995).

    Article  ADS  CAS  Google Scholar 

  32. Gasc, J.-P. Les rapports anatomiques du membre pelvien vestigial chez les squamates serpentiformes. Bull. Mus. Nat. Hist. 2e Ser. 38, 99–110 (1966).

    Google Scholar 

  33. Eyewitness Encyclopedia of Nature.(Dorling-Kindersley Multimedia, London, (1995).

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Acknowledgements

We thank Drayton Manor Zoo, Edinburgh Zoo, London Zoo, Welsh Mountain Zoo and J. Fletcher for fertile python eggs; M. Caldwell, A. Cohn, S. Evans, M. Ferguson, E. Kochva, M. Lee, C.O. Lovejoy, K. Patel, J. R. D. Stalvey, V. Wilson and L. Wolpert for discussion; M. Turmaine for assistance with scanning electron microscopy; and E. De Robertis, T. Jessell, A. Joyner, G. Martin, A.McMahon, G. Panganiban, C. Tabin, N. Wall, and R. Zeller for reagents. This research was funded by the BBSRC.

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Correspondence to Martin J .Cohn.

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.Cohn, M., Tickle, C. Developmental basis of limblessness and axial patterning in snakes. Nature 399, 474–479 (1999). https://doi.org/10.1038/20944

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