The Goitered Gazelle, Gazella subgutturosa, is the most widespread gazelle species in the Middle East and central Asia inhabiting desert and semi-desert habitats. Today it is threatened and its geographic range and population size have experienced significant decline in the last decades. In Iran, the remnant populations are confined to fragmented habitats. We aimed to characterise genetic diversity and phylogenetic status of the populations of Goitered Gazelle in Central Iran and to evaluate the potential effect of a historic population bottleneck on the genetic variation of today’s population. We used noninvasive sampling to uncover structure and level of genetic variation in a fragment of the cytochrome-b gene from 170 samples. Genealogical analyses were performed using HKY+I model and phylogenetic trees reconstructed using Bayesian inference and maximum likelihood. We found extremely low levels of genetic variation, with altogether only five haplotypes in samples from different populations. Overall haplotype diversity was 0.081 and nucleotide diversity 0.0003. The mean observed mismatch between any two sequences was 0.093 with the largest peak for small numbers. The mismatch distribution fit the model of population expansion and suggested that gazelles had experienced a sudden expansion. An unrooted median-joining network analysis of mtDNA haplotypes showed a star-like structure which few mutations steps separating the haplotypes from other regions. Our findings strengthen the urgency of preserving the species’ genetic diversity to prevent local extinction.

中文翻译：

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伊朗脆弱的甲状腺瞪羚，Gazella subgutturosa（Cetartiodactyla：Bovidae）的遗传多样性低：近期种群下降的潜在遗传后果

甲状腺肿瞪羚（Gazella subgutturosa）是中东和中亚地区分布最广的瞪羚物种，栖息于沙漠和半沙漠栖息地。今天它受到威胁，它的地理范围和人口规模在过去几十年中经历了显着下降。在伊朗，残余种群被限制在支离破碎的栖息地。我们旨在表征伊朗中部甲状腺瞪羚种群的遗传多样性和系统发育状况，并评估历史种群瓶颈对当今种群遗传变异的潜在影响。我们使用非侵入性采样来揭示来自 170 个样本的细胞色素 b 基因片段的结构和遗传变异水平。使用 HKY+I 模型和使用贝叶斯推理和最大似然重建的系统发育树进行谱系分析。我们发现遗传变异水平极低，来自不同人群的样本中总共只有五种单倍型。整体单倍型多样性为 0.081，核苷酸多样性为 0.0003。任何两个序列之间观察到的平均错配为 0.093，小数的最大峰值。错配分布符合种群扩张模型，表明瞪羚经历了突然的扩张。mtDNA 单倍型的无根中值连接网络分析显示出星状结构，其中很少有突变步骤将单倍型与其他区域分开。我们的发现加强了保护物种遗传多样性以防止局部灭绝的紧迫性。