Kawasaki K, Weiss K M
Department of Anthropology, Pennsylvania State University, University Park, PA 16802, USA.
J Dent Res. 2008 Jun;87(6):520-31. doi: 10.1177/154405910808700608.
Many genes critical to vertebrate skeletal mineralization are members of the secretory calcium-binding phosphoprotein (SCPP) gene family, which has evolved by gene duplication from a single ancestral gene. In humans, mutations in some of these SCPP genes have been associated with various diseases related to dentin or enamel hypoplasia. Recently, systematic searches for SCPP genes of various species have allowed us to investigate the history of phylogenetically variable dental tissues as a whole. One important conclusion is that not all disease-associated SCPP genes are present in tetrapods, and teleost fish probably have none, even in toothed species, having acquired their complement of SCPP genes through an independent duplication history. Here, we review comparative analyses of mineralized dental tissues, with particular emphasis on the use of SCPPs, within and between tetrapods and teleosts. Current knowledge suggests a close relationship among bone, dentin, teleost fish enameloid (enamel-like hard tissue), and tetrapod enamel. These tissues thus form a mineralized-tissue continuum. Contemporary dental tissues have evolved from an ancestral continuum through lineage-specific modifications.
许多对脊椎动物骨骼矿化至关重要的基因是分泌型钙结合磷蛋白（SCPP）基因家族的成员，该家族通过基因复制从单个祖先基因进化而来。在人类中，这些SCPP基因中的一些突变与多种与牙本质或釉质发育不全相关的疾病有关。最近，对各种物种的SCPP基因进行系统搜索，使我们能够整体研究系统发育可变的牙齿组织的历史。一个重要结论是，并非所有与疾病相关的SCPP基因都存在于四足动物中，硬骨鱼可能根本没有，即使在有齿物种中也是如此，它们通过独立的复制历史获得了SCPP基因的补充。在这里，我们回顾了四足动物和硬骨鱼内部以及它们之间矿化牙齿组织的比较分析，特别强调了SCPP的使用。目前的知识表明，骨、牙本质、硬骨鱼釉质样组织（类釉质硬组织）和四足动物釉质之间存在密切关系。因此，这些组织形成了一个矿化组织连续体。当代牙齿组织通过特定谱系的修饰从祖先连续体进化而来。
