Combining Morphology and Palaeogenomics to understand the Status and Contribution of Mules to Roman Equine Populations in Austria and Germany.

在进化和文化研究中，种间杂交是一个相关的话题。在这方面，考古、图像和文字资料表明，人类几千年来一直在杂交野生和家养的马科成员。本研究的重点是骡子，即雄性家驴和母马的杂交品种。由于所谓的杂种优势效应，骡子比亲本中的任何一种都更有效，因此作为劳动动物尤其受到重视，根据古典资料，骡子是成群繁殖的。然而，仅根据牙齿和骨形态特征在考古动物组合中识别骡子（和其他马科杂交种）是有问题的，而且容易在观察者之间产生相当大的差异。因此，应用传统的形态学方法可能不是很有效地充分说明骡子在古代文化中的作用。本研究旨在阐明在前罗马和罗马时代，德国东南部和奥地利的当地育种实践和骡子对马科动物种群的贡献。它将采用多学科方法，结合标准形态学、几何形态计量学（GMM）和古代DNA分析，以检验几个假设，即（H1）骡子代表了Raetia省（德国）、Noricum省和Upper Pannonia省（奥地利）罗马化过程的标志，（H2）阿尔卑斯分水岭以北的公驴（jackass）和母马（mare）之间没有杂交。这意味着动物必须从阿尔卑斯山脉以南的地区进口，在那里已经建立了杂交育种，并且（H3）罗马军队在Raetia对马的高需求不仅需要从其他地方进口，而且还涉及到从罗马之前的当地人口中继承当地马血统的繁殖努力。从方法论的角度来看，我们的项目希望建立一个可靠的遗传和GMM管道，用于系统地追踪马考古组合中的f1杂交种，从而能够验证基于标准形态学分析的鉴定。通过比较不同方法的结果，也将有可能量化在只有标准形态学分析才能进行的情况下识别杂交的准确性。总而言之，我们期望本文提出的综合方法将开辟更多的场所，以解决迄今为止被低估的马杂交在过去社会中的作用，同时显著提高我们对阿尔卑斯山北部罗马帝国骡子的文化、经济和军事历史的了解。

In evolutionary and cultural studies, interspecies hybridisation is a relevant topic. In this respect, humans have been crossbreeding wild and domestic members of the family Equidae since millennia, as illustrated by archaeological, iconographic and written sources. In focus of this study is the mule, the cross between the male domestic donkey and the mare. Being more effective than either of the parental stock, elicited by the so-called heterosis effect, mules were particularly valued as labour animals and according to Classical sources bred in numbers. However, identifying mules (and other equid hybrids) in archaeofaunal assemblages based solely on dental and osteomorphological features is problematic and prone to considerable inter-observer variation. Consequently, application of traditional morphological methods might not be very efficient to specifying adequately the role of mules in ancient cultures.This study aims at elucidating local breeding practices and the contribution of mules to the equid populations exploited in southeastern Germany and Austria in pre-Roman and Roman times. It will apply a multidisciplinary approach combining standard morphology with Geometric Morphometrics (GMM) and ancient DNA analysis in order testing several hypotheses, namely that (H1) the mule represents a marker for the process of Romanization in the Provinces Raetia (Germany), Noricum and Upper Pannonia (Austria), (H2) north of the Alpine divide hybridization between male donkeys (jackass) and female horses (mare) was not practiced, implying that animals had to be imported from regions south of the Alps where cross-breeding was already established, and (H3) the high demand for horses in Roman military service in Raetia not only necessitated imports from elsewhere but involved breeding efforts with local horse lineages descending from pre-Roman local populations. From a methodological viewpoint our project expects establishing a reliable genetic and GMM pipeline for tracing systematically F1-hybrids in equine archaeological assemblages, thus enabling to validate identifications based on standard morphological analyses. By comparing the results of the different approaches it will also be possible to quantify the degree of accuracy for recognizing hybrids in cases where only standard morphological analyses can be performed. In sum, we expect that the combined approach proposed here will open up additional venues to address the hitherto underestimated role of equine hybrids in past societies whilst significantly enhancing our knowledge of the cultural, economic and military history of the mule in the Roman Empire north of Alps.