Osborne Amy J, Pearson John, Chilvers B Louise, Kennedy Martin A, Gemmell Neil J
Department of Anatomy, University of Otago, Dunedin, New Zealand; Department of Pathology, University of Otago, Christchurch, New Zealand.
Department of Public Health and General Practice, University of Otago, Christchurch, New Zealand.
PLoS One. 2015 Apr 14;10(4):e0122703. doi: 10.1371/journal.pone.0122703. eCollection 2015.
The New Zealand sea lion (NZSL, Phocarctos hookeri) is a Threatened marine mammal with a restricted distribution and a small, declining, population size. The species is susceptible to bacterial pathogens, having suffered three mass mortality events since 1998. Understanding the genetic factors linked to this susceptibility is important in mitigating population decline. The gene solute carrier family 11 member a1 (Slc11a1) plays an important role in mammalian resistance or susceptibility to a wide range of bacterial pathogens. At present, Slc11a1 has not been characterised in many taxa, and despite its known roles in mediating the effects of infectious disease agents, has not been examined as a candidate gene in susceptibility or resistance in any wild population of conservation concern. Here we examine components of Slc11a1 in NZSLs and identify: i) a polymorphic nucleotide in the promoter region; ii) putative shared transcription factor binding motifs between canids and NZSLs; and iii) a conserved polymorphic microsatellite in the first intron of Slc11a1, which together suggest conservation of Slc11a1 gene structure in otariids. At the promoter polymorphism, we demonstrate a shift away from normal allele frequency distributions and an increased likelihood of death from infectious causes with one allelic variant. While this increased likelihood is not statistically significant, lack of significance is potentially due to the complexity of genetic susceptibility to disease in wild populations. Our preliminary data highlight the potential significance of this gene in disease resistance in wild populations; further exploration of Slc11a1 will aid the understanding of susceptibility to infection in mammalian species of conservation significance.
新西兰海狮（NZSL，Phocarctos hookeri）是一种濒危海洋哺乳动物，分布范围有限，种群数量少且呈下降趋势。该物种易受细菌病原体感染，自1998年以来已发生过三次大规模死亡事件。了解与这种易感性相关的遗传因素对于缓解种群数量下降至关重要。溶质载体家族11成员a1基因（Slc11a1）在哺乳动物对多种细菌病原体的抗性或易感性中起着重要作用。目前，Slc11a1在许多分类群中尚未得到表征，尽管已知其在介导传染病原体的作用方面发挥作用，但尚未在任何受保护的野生种群中作为易感性或抗性的候选基因进行研究。在此，我们研究了新西兰海狮中Slc11a1的组成部分，并确定了：i）启动子区域的一个多态核苷酸；ii）犬科动物和新西兰海狮之间假定的共享转录因子结合基序；iii）Slc11a1第一个内含子中的一个保守多态微卫星，这些共同表明海狗科动物中Slc11a1基因结构的保守性。在启动子多态性方面，我们证明了等位基因频率分布偏离正常情况，并且一种等位基因变体导致因感染性原因死亡的可能性增加。虽然这种增加的可能性在统计学上不显著，但缺乏显著性可能是由于野生种群中疾病遗传易感性的复杂性。我们的初步数据突出了该基因在野生种群抗病性中的潜在重要性；对Slc11a1的进一步探索将有助于理解具有保护意义的哺乳动物物种对感染的易感性。
