A test for paedomorphism in domestic pig cranial morphology.

Allowen Evin,Thomas Cucchi,Keith Dobney,Greger Larson,Mélanie Debiais-Thibaud,Una Strand Vidarsdottir,Joseph Owen

doi:10.1098/rsbl.2017.0321

Abstract

Domestic animals are often described as paedomorphic, meaning that they retain juvenile characteristics into adulthood. Through a three-dimensional landmark-based geometric morphometric analysis of cranial morphology at three growth stages, we demonstrate that wild boar (n = 138) and domestic pigs (n = 106) (Sus scrofa) follow distinct ontogenetic trajectories. With the exception of the size ratio between facial and neurocranial regions, paedomorphism does not appear to be the primary pattern describing the observed differences between wild and domestic pig cranial morphologies. The cranial phenotype of domestic pigs instead involves developmental innovation during domestication. This result questions the long-standing assumption that domestic animal phenotypes are paedomorphic forms of their wild counterparts.

Highlights

The process of domestication is characterized by significant changes in morphology and behaviour that differentiate domestic forms from their wild relatives [1,2]
Through a three-dimensional landmark-based geometric morphometric analysis of cranial morphology at three growth stages, we demonstrate that wild boar (n 1⁄4 138) and domestic pigs (n 1⁄4 106) (Sus scrofa) follow distinct ontogenetic trajectories
Developmental changes initiated before birth and accentuated by distinct post-natal growth trajectories are responsible for the domestic pig’s cranial morphology

Summary

Introduction

The process of domestication is characterized by significant changes in morphology and behaviour that differentiate domestic forms from their wild relatives [1,2]. The fact that these differences are observed consistently in a wide range of taxonomically unrelated domestic mammals implies that a similar evolutionary process is responsible for domestic phenotypes [2,3,4,5]. [4,7]), meaning that they retain ancestral (wild) juvenile characteristics into adulthood [8] This paedomorphic pattern can be obtained through neoteny ( called juvenilization) characterized by a delay in shape changes relative to an unchanged size [8].

Methods

Discussion

Conclusion