The genetics of odontogenesis: implications in dental anthropology and palaeo-odontology

Abstract

Palaeoanthropology and forensic odontology rely significantly on detailed dental morphology that is ultimately the phenotypic expression of the underlying genotype and developmental phenomena. Odontogenesis is the consequence of a complex series of molecular interactions controlled by epigenetic signals acting on embryonic epithelial-mesenchymal tissues of ectodermal, neural crest and mesodermal origin. Of the estimated 24 847 genes of the human genome (Pearson, 2003) some 200 or more genes have been directly or indirectly implicated in tooth development (http://bite-it.helsinki.fi). The loci of these genes on the 22 pairs of autosomes and the pair of sex chromosomes are being identified by their mutations that give rise to phenotypic dental abnormalities. The sequential cascades of stages from initiation through the bud, cap, bell, mineralisation, root formation and eruption of teeth are all under genetic control but subject to environmental influences. Identification of specific genes with clinical phenotypes provides invaluable clues to familial, racial and evolutionary affinities, all of jurisprudential, heredity and evolutionary significance to odontologists. Combining the genetics of odontogenesis with forensic evidence and palaeoanthropological fossil data provides an unparalleled source of information on heredity, environmental and evolutionary events through teeth, the most durable of all biological structures after death. It is paradoxical that teeth are most susceptible to decay during life, but postmortem are the last structures to disintegrate. Teeth truly tell tales of the living and the dead.