Data from: Origins of cattle on Chirikof Island, Alaska, elucidated from genome-wide SNP genotypes

Feral livestock may harbor genetic variation of commercial, scientific, historical or esthetic value. The origins and uniqueness of feral cattle on Chirikof Island, Alaska, are uncertain. The island is now part of the Alaska Maritime Wildlife Refuge and Federal wildlife managers want grazing to cease, presumably leading to demise of the cattle. Here we characterize the cattle of Chirikof Island relative to extant breeds and discern their origins. Our analyses support the inference that Yakut cattle from Russia arrived first on Chirikof Island, then ~120 years ago the first European taurine cattle were introduced to the island, and finally a large wave of Hereford cattle were introduced on average 40 years ago. In addition, this mixture of European and East-Asian cattle is unique compared with other North American breeds and we find evidence that natural selection in the relatively harsh environment of Chirikof Island has further impacted their genetic architecture. These results provide an objective basis for decisions regarding conservation of the Chirikof Island cattle.

野生家畜可能携带有具备商业、科研、历史或观赏价值的遗传变异。阿拉斯加奇里科夫岛（Chirikof Island）上的野生牛群的起源与独特性目前尚不明确。目前该岛已划归阿拉斯加海洋野生动物保护区（Alaska Maritime Wildlife Refuge）管理，联邦野生动物管理人员计划停止放牧，这或将导致岛上牛群最终消亡。本研究对奇里科夫岛的牛群进行了遗传特征解析，并与现存牛品种开展对比分析，以追溯其起源。分析结果支持如下推论：来自俄罗斯的雅库特牛（Yakut cattle）最先抵达奇里科夫岛；约120年前，首批欧洲普通牛（European taurine cattle）被引入该岛；而平均在40年前，又有大规模的赫里福德牛（Hereford cattle）被引入此地。此外，与其他北美牛品种相比，这种欧洲与东亚牛类的混合种群具有独特性；研究还发现，奇里科夫岛相对严苛的自然环境所带来的自然选择，进一步影响了该种群的遗传结构。本研究结果为奇里科夫岛牛群的保护决策提供了客观依据。