title: Pervasive genetic integration directs the evolution of human skull shape.
abstract: It has long been unclear whether the different derived cranial traits of modern humans evolved independently in response to separate selection pressures or whether they resulted from the inherent morphological integration throughout the skull. In a novel approach to this issue, we combine evolutionary quantitative genetics and geometric morphometrics to analyze genetic and phenotypic integration in human skull shape. We measured human skulls in the ossuary of Hallstatt (Austria), which offer a unique opportunity because they are associated with genealogical data. Our results indicate pronounced covariation of traits throughout the skull. Separate simulations of selection for localized shape changes corresponding to some of the principal derived characters of modern human skulls produced outcomes that were similar to each other and involved a joint response in all of these traits. The data for both genetic and phenotypic shape variation were not consistent with the hypothesis that the face, cranial base, and cranial vault are completely independent modules but relatively strongly integrated structures. These results indicate pervasive integration in the human skull and suggest a reinterpretation of the selective scenario for human evolution where the origin of any one of the derived characters may have facilitated the evolution of the others.
authors.affiliation: Departament de Biologia Animal, Universitat de Barcelona, Barcelona, Spain. nmartinezabadias@gmail.com
authors.forename: Neus
authors.initials: N
authors.lastname: Martínez-Abadías
authors.forename: Mireia
authors.initials: M
authors.lastname: Esparza
authors.forename: Torstein
authors.initials: T
authors.lastname: Sjøvold
authors.forename: Rolando
authors.initials: R
authors.lastname: González-José
authors.forename: Mauro
authors.initials: M
authors.lastname: Santos
authors.forename: Miquel
authors.initials: M
authors.lastname: Hernández
authors.forename: Christian Peter
authors.initials: CP
authors.lastname: Klingenberg
mesh_terms: D001317:Austria; D005075:Biological Evolution; D002508:Cephalometry; D005145:Face / Q000033:anatomy & histology; D005260:Female; D006801:Humans; D008297:Male; D008445:Maxillofacial Development; D010641:Phenotype; D019655:Quantitative Trait, Heritable; D012641:Selection, Genetic; D012886:Skull / Q000033:anatomy & histology* / Q000254:growth & development*; D019291:Skull Base / Q000033:anatomy & histology / Q000254:growth & development