Evolutionary Biology

, Volume 36, Issue 1, pp 37–56

Developmental and Genetic Constraints on Neurocranial Globularity: Insights from Analyses of Deformed Skulls and Quantitative Genetics

  • Neus Martínez-Abadías
  • Carolina Paschetta
  • Soledad de Azevedo
  • Mireia Esparza
  • Rolando González-José
Research Article

DOI: 10.1007/s11692-008-9045-4

Cite this article as:
Martínez-Abadías, N., Paschetta, C., de Azevedo, S. et al. Evol Biol (2009) 36: 37. doi:10.1007/s11692-008-9045-4

Abstract

Neurocranial globularity is one of the few derived traits defining anatomically modern humans. Variations in this trait derive from multiple and complex interactions between portions of the brain and the size and shape of the cranial base, among other factors. Given their evolutionary and functional importance, neurocranial globularity is expected to present high genetic and developmental constraints on their phenotypic expression. Here we applied two independent approaches to investigate both types of constraints. First, we assessed if patterns of morphological integration are conserved or else disrupted on a series of artificially deformed skulls in comparison to non-deformed (ND) ones. Second, after the estimation of the genetic covariance matrix for human skull shape, we explored how neurocranial globularity would respond to putative selective events disrupting the normal morphological patterns. Simulations on these deviations were explicitly set to replicate the artificial deformation patterns in order to compare developmental and genetic constraints under the same biomechanical conditions. In general terms, our results indicate that putative developmental constraints help to preserve some aspects of normal morphological integration even in the deformed skulls. Moreover, we find that the response to selection in neurocranial globularity is pervasive. In other words, induced changes in the vault generate a global response, indicating that departures from normal patterns of neurocranial globularity are genetically constrained. In summary, our combined results suggest that neurocranial globularity behaves as a highly genetic and developmental constrained trait.

Keywords

Constraints Neurocranial globularity Quantitative genetics Geometric morphometrics Morphological integration Artificial deformation 

Supplementary material

11692_2008_9045_MOESM1_ESM.doc (30 kb)
MOESM1 (DOC 30 kb)
11692_2008_9045_MOESM2_ESM.tif (1.3 mb)
Landmarks used in the analysis of deformed and non-deformed skulls. Three-dimensional landmarks depicting facial (top), vault (center), and basal (bottom) configurations are shown separately. The interlandmark distances describing vault, facial, and basal length and width are shown as red lines (see Table S1 for definitions) (TIF 1,324 kb)
11692_2008_9045_MOESM3_ESM.tif (611 kb)
Landmarks used in the analysis of the G-matrix (TIF 612 kb)

Copyright information

© Springer Science+Business Media, LLC 2008

Authors and Affiliations

  • Neus Martínez-Abadías
    • 1
  • Carolina Paschetta
    • 2
  • Soledad de Azevedo
    • 2
  • Mireia Esparza
    • 1
  • Rolando González-José
    • 2
  1. 1.Secció d’Antropologia, Departament de Biologia AnimalUniversitat de Barcelona. Av. DiagonalBarcelonaSpain
  2. 2.Centro Nacional PatagónicoConsejo Nacional de Investigaciones Científicas y Técnicas (CONICET)Puerto MadrynArgentina

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