PDF(Pubmed)
Abstract：
Domestication has long been considered the most powerful evolutionary engine behind dramatic reductions in brain size in several taxa, and the dog (Canis familiaris) is considered as a typical example that shows a substantial decrease in brain size relative to its ancestor, the grey wolf (Canis lupus). However, to make the case for exceptional evolution of reduced brain size under domestication requires an interspecific approach in a phylogenetic context that can quantify the extent by which domestication reduces brain size in comparison to closely related non-domesticated species responding to different selection factors in the wild. Here, we used a phylogenetic method to identify evolutionary singularities to test if the domesticated dog stands out in terms of relative brain size from other species of canids. We found that the dog does not present unambiguous signature of evolutionary singularity with regard to its small brain size, as the results were sensitive to the considerations about the ancestral trait values upon domestication. However, we obtained strong evidence for the hibernating common raccoon dog (Nyctereutes procyonoides) being an evolutionary outlier for its brain size. Therefore, domestication is not necessarily an exceptional case concerning evolutionary reductions in brain size in an interspecific perspective.
摘要：
驯化一直被认为是最强大的进化引擎，在几个分类单元中大脑体积急剧减少，狗（犬属犬）被认为是一个典型的例子，显示相对于其祖先，大脑大小大幅减少，灰狼（Canis狼疮）。然而,为了证明在驯化下大脑大小减小的异常进化，需要在系统发育环境中采用种间方法，该方法可以量化与密切相关的非驯化物种对不同选择因素的反应相比，驯化减少大脑大小的程度。这里,我们使用系统发育方法来识别进化奇点，以测试驯养的狗是否在相对大脑大小方面与其他犬科动物相比脱颖而出。我们发现，就其小的大脑而言，这只狗并没有表现出明确的进化奇点特征，因为结果对驯化后祖先性状值的考虑很敏感。然而,我们获得了强有力的证据，证明冬眠的普通浣熊犬（Nyctereutesprocyonoides）是其大脑大小的进化异常值。因此,从种间的角度来看，驯化不一定是关于大脑大小的进化减少的例外情况。
