Data from: Genome-wide SNP analysis unveils genetic structure and phylogeographic history of snow sheep (Ovis nivicola) populations inhabiting the Verkhoyansk Mountains and Momsky Ridge (northeastern Siberia)

Insights into the genetic characteristics of a species provide important
information for wildlife conservation programs. Here, we used the
OvineSNP50 BeadChip developed for domestic sheep to examine population
structure and evaluate genetic diversity of snow sheep (Ovis nivicola)
inhabiting Verkhoyansk Range and Momsky Ridge. A total of 1121 polymorphic
SNPs were used to test 80 specimens representing five populations,
including four populations of the Verkhoyansk Mountain chain: Kharaulakh
Ridge–Tiksi Bay (TIK, n = 22), Orulgan Ridge (ORU, n = 22), the central
part of Verkhoyansk Range (VER, n = 15), Suntar-Khayata Ridge (SKH, n =
13), and Momsky Ridge (MOM, n = 8). We showed that the studied populations
were genetically structured according to a geographical pattern. Pairwise
FST values ranged from 0.044 to 0.205. Admixture analysis identified K = 2
as the most likely number of ancestral populations. A Neighbor-Net tree
showed that TIK was an isolated group related to the main network through
ORU. TreeMix analysis revealed that TIK and MOM originated from two
different ancestral populations and detected gene flow from MOM to ORU.
This was supported by the f3 statistic, which showed that ORU is an
admixed population with TIK and MOM/SKH heritage. Genetic diversity in the
studied groups was increasing southward. Minimum values of observed (Ho)
and expected (He) heterozygosity and allelic richness (Ar) were observed
in the most northern population–TIK, and maximum values were observed in
the most southern population–SKH. Thus, our results revealed clear genetic
structure in the studied populations of snow sheep and showed that TIK has
a different origin from MOM, SKH and VER even though they are
conventionally considered a single subspecies known as Yakut snow sheep
(Ovis nivicola lydekkeri). Most likely, TIK was an isolated group during
the late Pleistocene glaciations of Verkhoyansk Range.

对某一物种遗传特征的深入解析，可为野生动物保护计划提供关键科学依据。本研究采用针对家羊开发的绵羊50K SNP分型芯片（OvineSNP50 BeadChip），对栖息于维尔霍扬斯克山脉（Verkhoyansk Range）和莫姆斯基岭（Momsky Ridge）的雪羊（Ovis nivicola）开展群体结构分析与遗传多样性评估。
本研究共使用1121个多态性单核苷酸多态性（SNP）位点，对代表5个群体的80份样本进行分型检测：其中4个群体隶属于维尔霍扬斯克山系，分别为哈拉乌拉赫岭-季克西湾群体（TIK，n=22）、奥鲁尔干岭群体（ORU，n=22）、维尔霍扬斯克山脉中部群体（VER，n=15）、孙塔尔-哈亚塔岭群体（SKH，n=13），剩余1个为莫姆斯基岭群体（MOM，n=8）。
研究结果显示，受试雪羊群体的遗传结构呈现显著的地理分布模式。两两群体间的固定指数（FST）取值范围为0.044至0.205。Admixture群体遗传混合分析表明，最可能的祖先群体数目为K=2。邻接网（Neighbor-Net）系统发育树显示，TIK群体为独立分支，仅通过ORU群体与主系统发育网络相连。TreeMix群体历史演化分析显示，TIK与MOM群体源自两个不同的祖先群体，且检测到MOM群体向ORU群体的基因流事件。f3统计量分析进一步验证了该结果，表明ORU群体为混合群体，其遗传背景兼具TIK与MOM/SKH群体的特征。
受试群体的遗传多样性呈南高北低的纬度梯度分布：最北端的TIK群体观测杂合度（Ho）、期望杂合度（He）及等位基因丰富度（Ar）均为最低值，而最南端的SKH群体则为最高值。
综上，本研究结果明确揭示了受试雪羊群体的遗传结构特征：尽管传统分类学上将所有受试群体归为单一亚种——雅库特雪羊（Ovis nivicola lydekkeri），但TIK群体的起源与MOM、SKH及VER群体存在显著差异。推测在维尔霍扬斯克山脉晚更新世冰期阶段，TIK群体即已形成独立的演化支系。