This research utilizes geometric morphometrics to investigate shape variation in the skull, mandible, and teeth among three rat strains: Wistar Albino (WA), Sprague Dawley (SD), and WAG/Rij (WR). Through the analysis of 48 rats using 2D geometric morphometric techniques, significant differences in their skull morphology were identified. This study indicates a shift from a rectangular to an oval cranial shape across strains, with notable size and morphological variances. Particularly, the WR strain’s skull shape significantly differs from the SD and WA strains, suggesting distinct ecological or genetic pathways. Compared to the skull, mandible shape differences are less pronounced, but still significant. The WR strain exhibits a distinct mandible shape, potentially reflecting ecological adaptations like dietary habits. The teeth shape of WR rats is the most distinct. SD rats consistently exhibited larger sizes in both skull and mandible measurements, while WR rats were notably smaller. Interestingly, sexual dimorphism was not statistically significant in skull and teeth sizes, aligning with findings from previous studies. However, the mandible showed clear size differences between sexes, underscoring its potential for adaptive or behavioral studies. In summary, this study provides a comprehensive analysis of morphological variations in rat strains, highlighting the intricate interplay of size, shape, and ecological factors. These findings lay a foundation for deeper explorations into the adaptive, ecological, or genetic narratives influencing rat morphology.

中文翻译：

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Wistar Albino、Sprague Dawley 和 WAG/Rij 大鼠品系的颅骨几何形态测量比较

这项研究利用几何形态测量学来研究三种大鼠品系的头骨、下颌骨和牙齿的形状变化：Wistar Albino (WA)、Sprague Dawley (SD) 和 WAG/Rij (WR)。通过使用 2D 几何形态测量技术对 48 只大鼠进行分析，发现了它们头骨形态的显着差异。这项研究表明，不同品系的颅骨形状从矩形转变为椭圆形，且尺寸和形态差异显着。特别是，WR 品系的头骨形状与 SD 和 WA 品系显着不同，表明存在不同的生态或遗传途径。与头骨相比，下颌骨形状差异不太明显，但仍然很重要。 WR品系表现出独特的下颌骨形状，可能反映了饮食习惯等生态适应。 WR大鼠的牙齿形状最为明显。 SD 大鼠在头骨和下颌骨测量中始终表现出较大的尺寸，而 WR 大鼠则明显较小。有趣的是，性别二态性在头骨和牙齿大小方面没有统计学意义，这与之前的研究结果一致。然而，下颌骨在性别之间表现出明显的尺寸差异，强调了其适应性或行为研究的潜力。总之，本研究对大鼠品系的形态变异进行了全面分析，强调了体型、形状和生态因素之间错综复杂的相互作用。这些发现为更深入地探索影响大鼠形态的适应性、生态或遗传叙述奠定了基础。