Institute of Agricultural Biology and Biotechnology, National Research Council, via Edoardo Bassini, 15, 20133, Milan, Italy.
GenPhySE, Université de Toulouse, INRAE, ENVT, 31326, Castanet-Tolosan, France.
Sci Rep. 2023 Nov 25;13(1):20728. doi: 10.1038/s41598-023-48005-8.
In the last decade, several studies aimed at dissecting the genetic architecture of local small ruminant breeds to discover which variations are involved in the process of adaptation to environmental conditions, a topic that has acquired priority due to climate change. Considering that traditional breeds are a reservoir of such important genetic variation, improving the current knowledge about their genetic diversity and origin is the first step forward in designing sound conservation guidelines. The genetic composition of North-Western European archetypical goat breeds is still poorly exploited. In this study we aimed to fill this gap investigating goat breeds across Ireland and Scandinavia, including also some other potential continental sources of introgression. The PCA and Admixture analyses suggest a well-defined cluster that includes Norwegian and Swedish breeds, while the crossbred Danish landrace is far apart, and there appears to be a close relationship between the Irish and Saanen goats. In addition, both graph representation of historical relationships among populations and f4-ratio statistics suggest a certain degree of gene flow between the Norse and Atlantic landraces. Furthermore, we identify signs of ancient admixture events of Scandinavian origin in the Irish and in the Icelandic goats. The time when these migrations, and consequently the introgression, of Scandinavian-like alleles occurred, can be traced back to the Viking colonisation of these two isles during the Viking Age (793-1066 CE). The demographic analysis indicates a complicated history of these traditional breeds with signatures of bottleneck, inbreeding and crossbreeding with the improved breeds. Despite these recent demographic changes and the historical genetic background shaped by centuries of human-mediated gene flow, most of them maintained their genetic identity, becoming an irreplaceable genetic resource as well as a cultural heritage.
在过去的十年中，有几项研究旨在剖析本地小反刍动物品种的遗传结构，以发现哪些变异与适应环境条件的过程有关，由于气候变化，这个主题变得越来越重要。考虑到传统品种是这种重要遗传变异的储存库，因此提高对其遗传多样性和起源的现有认识是制定合理保护准则的第一步。北欧典型山羊品种的遗传组成仍未得到充分利用。在这项研究中，我们旨在通过调查爱尔兰和斯堪的纳维亚的山羊品种来填补这一空白，其中还包括一些其他可能的大陆渗入来源。PCA 和 Admixxture 分析表明，包括挪威和瑞典品种在内的一个定义明确的集群，而杂交丹麦兰德瑞斯则相距甚远，并且爱尔兰和萨能山羊之间似乎存在密切关系。此外，种群之间历史关系的图形表示和 f4-ratio 统计数据表明，北欧和大西洋兰德瑞斯之间存在一定程度的基因流动。此外，我们在爱尔兰和冰岛山羊中发现了与斯堪的纳维亚起源有关的古代混合事件的迹象。这些斯堪的纳维亚样等位基因的迁移，以及随之而来的渗入，发生的时间可以追溯到维京时代（公元 793-1066 年）这两个岛屿的维京人殖民时期。人口分析表明，这些传统品种的历史复杂，存在瓶颈、近亲繁殖和与改良品种杂交的特征。尽管最近发生了这些人口变化以及由数百年的人为基因流动塑造的历史遗传背景，但它们中的大多数仍保持其遗传身份，成为一种不可替代的遗传资源和文化遗产。
