Paleontology has long relied on assumptions about the genetic and developmental influences on skeletal variation. The last few decades of developmental genetics have elucidated the genetic pathways involved in making teeth and patterning the dentition. Quantitative genetic analyses have refined this genotype:phenotype map even more, especially for primates. We now have the ability to define dental traits with a fair degree of fidelity to the underlying genetic architecture; for example, the molar module component (MMC) and the premolar-molar module (PMM) that have been defined through quantitative genetic analyses. We leverage an extensive dataset of extant and extinct hominoid dental variation to explore how these two genetically patterned phenotypes have evolved through time. We assess MMC and PMM to test the hypothesis that these two traits reveal a more biologically informed taxonomy at the genus and species levels than do more traditional measurements. Our results indicate that MMC values for hominids fall into two categories and that Homo is derived compared with earlier taxa. We find a more variable, species-level pattern for PMM. These results, in combination with previous research, demonstrate that MMC reflects the phenotypic output of a more evolutionarily stable, or phylogenetically congruent, genetic mechanism, and PMM is a reflection of a more evolutionarily labile mechanism. These results suggest that the human lineage since the split with chimpanzees may not represent as much genus-level variation as has been inferred from traits whose etiologies are not understood.

中文翻译：

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一种测试人类分类学假设的基因型：表型方法。

长期以来，古生物学一直依赖关于骨骼变异的遗传和发育影响的假设。过去几十年的发育遗传学已经阐明了制造牙齿和牙列模式的遗传途径。定量遗传学分析进一步完善了这种基因型：表型图谱，特别是对于灵长类动物。现在，我们能够以基本的遗传结构保真度来定义牙齿特征。例如，通过定量遗传分析确定的磨牙模块组件（MMC）和前磨牙模块（PMM）。我们利用现有和已灭绝的类人牙齿变异的广泛数据集来探索这两种遗传模式表型如何随时间演变。我们评估MMC和PMM，以检验以下假设：与传统测量方法相比，这两个性状在属和物种水平上揭示了更为生物学的分类学。我们的结果表明，原始人的MMC值分为两类，与较早的分类单元相比，人是派生的。我们发现PMM的物种级别模式更加可变。这些结果与先前的研究相结合，表明MMC反映了一种在进化上更稳定，或在系统发育上一致的遗传机制的表型输出，而PMM则在进化上更加不稳定。这些结果表明，由于用黑猩猩进行的分裂，人类谱系可能不像从病因不明的特征中推断出的那样，代表着更多的属水平变异。