Ritzman Terrence B, Banovich Nicholas, Buss Kaitlin P, Guida Jennifer, Rubel Meagan A, Pinney Jennifer, Khang Bao, Ravosa Matthew J, Stone Anne C
Department of Neuroscience, Washington University School of Medicine, St. Louis, MO, USA; Department of Archaeology, University of Cape Town, Cape Town, South Africa; Human Evolution Research Institute, University of Cape Town, Cape Town, South Africa; School of Human Evolution and Social Change, Arizona State University, Tempe, AZ, USA.
School of Human Evolution and Social Change, Arizona State University, Tempe, AZ, USA; Department of Human Genetics, University of Chicago, Chicago, IL, USA.
J Hum Evol. 2017 Oct;111:139-151. doi: 10.1016/j.jhevol.2017.06.014. Epub 2017 Aug 9.
The phylogenetic and adaptive factors that cause variation in primate facial form-including differences among the major primate clades and variation related to feeding and/or social behavior-are relatively well understood. However, comparatively little is known about the genetic mechanisms that underlie diversity in facial form in primates. Because it is essential for osteoblastic differentiation and skeletal development, the runt-related transcription factor 2 (Runx2) is one gene that may play a role in these genetic mechanisms. Specifically, polymorphisms in the QA ratio (determined by the ratio of the number of polyglutamines to polyalanines in one functional domain of Runx2) have been shown to be correlated with variation in facial length and orientation in other mammal groups. However, to date, the relationship between variation in this gene and variation in facial form in primates has not been explicitly tested. To test the hypothesis that the QA ratio is correlated with facial form in primates, the current study quantified the QA ratio, facial length, and facial angle in a sample of 33 primate species and tested for correlation using phylogenetic generalized least squares. The results indicate that the QA ratio of the Runx2 gene is positively correlated with variation in relative facial length in anthropoid primates. However, no correlation was found in strepsirrhines, and there was no correlation between facial angle and the QA ratio in any groups. These results suggest that, in primates, the QA ratio of the Runx2 gene may play a role in modulating facial size, but not facial orientation. This study therefore provides important clues about the genetic and developmental mechanisms that may underlie variation in facial form in primates.
导致灵长类动物面部形态出现差异的系统发育和适应性因素——包括主要灵长类进化枝之间的差异以及与进食和/或社会行为相关的变异——已得到较好的理解。然而，对于灵长类动物面部形态多样性背后的遗传机制，人们了解得相对较少。 runt相关转录因子2（Runx2）是一种可能在这些遗传机制中发挥作用的基因，因为它对成骨细胞分化和骨骼发育至关重要。具体而言，QA比率（由Runx2一个功能域中聚谷氨酰胺与聚丙氨酸的数量之比决定）的多态性已被证明与其他哺乳动物群体的面部长度和方向变异相关。然而，迄今为止，该基因变异与灵长类动物面部形态变异之间的关系尚未得到明确验证。为了验证QA比率与灵长类动物面部形态相关的假设，本研究对33种灵长类动物样本的QA比率、面部长度和面部角度进行了量化，并使用系统发育广义最小二乘法测试了相关性。结果表明，Runx2基因的QA比率与类人猿灵长类动物的相对面部长度变异呈正相关。然而，在原猴亚目动物中未发现相关性，并且在任何群体中面部角度与QA比率之间均无相关性。这些结果表明，在灵长类动物中，Runx2基因的QA比率可能在调节面部大小方面发挥作用，但在调节面部方向方面不起作用。因此，本研究为灵长类动物面部形态变异背后可能存在遗传和发育机制提供了重要线索。
