The pace of morphological change: historical transformation of skull shape in St Bernard dogs
The pace of morphological change: historical transformation of skull shape in St Bernard dogs
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DOI：
10.1098/rspb.2007.1169
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发表时间：
2008-01-07
影响因子：
4.7
通讯作者：
Klingenberg, Christian Peter
中科院分区：
文献类型：
--
作者：
Drake, Abby Grace;Klingenberg, Christian Peter
由于家养狗（Canis familiaris）的形态多样性，对狗头骨历史形态变化的研究为研究形态进化的动力学提供了一个极好的机会。品种标准使育种者知道哪些特征是被选择的。本文采用几何形态计量学的方法，研究了近120年来一系列纯种圣伯纳犬颅骨形状的变化。形状随时间的回归是非常显著的，并揭示了形状变化的一致趋势，与品种标准认为理想的特征相对应。圣伯纳犬历史上的形状变化包括颅骨的拓宽，上颚和上颚相对于颅骨的其余部分的倾斜。这一趋势在整个时期似乎是线性的，而且似乎还在继续。异速生长被排除为导致这种变化的一个因素，因为在历史上颅骨大小的变化没有一致的趋势，因为静态异速生长和个体发生异速生长的模式都不符合历史上的形状变化。圣伯纳头骨的戏剧性变化表明，选择可以实现持续和实质性的变化，并可以完全克服异速生长等限制。
Owing to the great morphological diversity of domestic dogs (Canis familiaris), the study of historical shape change in dog skulls provides an excellent opportunity for investigating the dynamics of morphological evolution. Breed standards make known which features were selected by breeders. Here we use the methods of geometric morphometrics to study change of skull shape in a series of purebred St Bernard dogs spanning nearly 120 years. A regression of shape on time was highly significant and revealed a consistent trend of shape change that corresponded to the features deemed desirable by the breed standard. Historical shape change in St Bernards involves a broadening of the skull and a tilting of the palate and upper jaw relative to the rest of the skull. This trend appears to be linear throughout the entire period and appears to be continuing. Allometry was ruled out as a contributing factor to this change because there was no consistent trend of historical change in skull size and because neither the patterns of static nor ontogenetic allometry corresponded to the historical shape change. The dramatic modification of the St Bernard skull demonstrates that selection can achieve sustained and substantial change and can completely overcome constraints such as allometry.