Hybridization is a natural process at species range boundaries, but increasing numbers of species are hybridizing due to direct or indirect human activities. In such cases of anthropogenic hybridization, subsequent introgression can threaten the survival of native species. To date, many such systems have been studied with too few genetic markers to assess the level of threat resulting from advanced backcrossing. Here, we use 44,999 single nucleotide polymorphisms (SNPs) and the ADMIXTURE program to study two areas of Scotland where a panel of 22 diagnostic microsatellites previously identified introgression between native red deer (Cervus elaphus) and introduced Japanese sika (Cervus nippon). In Kintyre, we reclassify 26% of deer from the pure species categories to the hybrid category whereas in the NW Highlands we only reclassify 2%. As expected, the reclassified individuals are mostly advanced backcrosses. We also investigate the ability of marker panels selected on different posterior allele frequency criteria to find hybrids assigned by the full marker set and show that in our data, ancestry informative markers (i.e. those that are highly differentiated between the species, but not fixed) are better than diagnostic markers (those markers that are fixed between the species) because they are more evenly distributed in the genome. Diagnostic loci are concentrated on the X chromosome to the detriment of autosomal coverage.

中文翻译：

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遗传标记密度的增加揭示了苏格兰金泰尔红鹿和引进的日本梅花鹿之间的高度混合。


杂交是物种范围边界上的自然过程，但由于直接或间接的人类活动，越来越多的物种正在杂交。在这种人为杂交的情况下，随后的基因渗入可能会威胁本地物种的生存。迄今为止，许多此类系统的遗传标记太少，无法评估高级回交造成的威胁水平。在这里，我们使用 44,999 个单核苷酸多态性 (SNP) 和 ADMIXTURE 程序来研究苏格兰的两个地区，其中由 22 个诊断微卫星组成的小组先前识别出本地马鹿 ( Cervus elaphus ) 和引入的日本梅花鹿 ( Cervus nippon ) 之间的基因渗入。在 Kintyre，我们将 26% 的鹿从纯种类别重新分类为混合类别，而在西北高地，我们仅重新分类 2%。正如预期的那样，重新分类的个体大多是高级回交。我们还研究了根据不同后等位基因频率标准选择的标记组的能力，以找到由完整标记集指定的杂种，并表明在我们的数据中，祖先信息标记（即在物种之间高度分化但不固定的标记）是比诊断标记（物种之间固定的标记）更好，因为它们在基因组中分布更均匀。诊断位点集中在 X 染色体上，不利于常染色体覆盖。