Bayas-Rea Rosa de Los Ángeles, Félix Fernando, Montufar Rommel
Escuela de Ciencias Biológicas, Pontificia Universidad Católica del Ecuador, Quito, Ecuador.
Museo de Ballenas, Salinas, Ecuador.
PeerJ. 2018 Apr 9;6:e4589. doi: 10.7717/peerj.4589. eCollection 2018.
The common bottlenose dolphin, , is widely distributed along the western coast of South America. In Ecuador, a resident population of bottlenose dolphins inhabits the inner estuarine area of the Gulf of Guayaquil located in the southwestern part of the country and is under threat from different human activities in the area. Only one genetic study on South American common bottlenose dolphins has been carried out to date, and understanding genetic variation of wildlife populations, especially species that are identified as threatened, is crucial for defining conservation units and developing appropriate conservation strategies. In order to evaluate the evolutionary link of this population, we assessed the phylogenetic relationships, phylogeographic patterns, and population structure using mitochondrial DNA (mtDNA). The sampling comprised: (i) 31 skin samples collected from free-ranging dolphins at three locations in the Gulf of Guayaquil inner estuary, (ii) 38 samples from stranded dolphins available at the collection of the "Museo de Ballenas de Salinas," (iii) 549 mtDNA control region (mtDNA CR) sequences from GenBank, and (iv) 66 concatenated sequences from 7-mtDNA regions (, , NADH dehydrogenase subunit I-II, cytochrome oxidase I and II, cytochrome b, and CR) obtained from mitogenomes available in GenBank. Our analyses indicated population structure between both inner and outer estuary dolphin populations as well as with distinct populations of using mtDNA CR. Moreover, the inner estuary bottlenose dolphin (estuarine bottlenose dolphin) population exhibited lower levels of genetic diversity than the outer estuary dolphin population according to the mtDNA CR. Finally, the estuarine bottlenose dolphin population was genetically distinct from other populations based on mtDNA CR and 7-mtDNA regions. From these results, we suggest that the estuarine bottlenose dolphin population should be considered a distinct lineage. This dolphin population faces a variety of anthropogenic threats in this area; thus, we highlight its fragility and urge authorities to issue prompt management and conservation measures.
普通宽吻海豚（学名：Tursiops truncatus）广泛分布于南美洲西海岸。在厄瓜多尔，一群常驻的宽吻海豚栖息在该国西南部瓜亚基尔湾的内河口区域，正受到该地区不同人类活动的威胁。迄今为止，仅对南美洲普通宽吻海豚进行过一项基因研究，而了解野生动物种群的基因变异，尤其是被认定为受威胁的物种，对于确定保护单元和制定适当的保护策略至关重要。为了评估这一种群的进化联系，我们利用线粒体DNA（mtDNA）评估了系统发育关系、系统地理学模式和种群结构。采样包括：（i）从瓜亚基尔湾内河口三个地点的自由放养海豚身上采集的31份皮肤样本，（ii）从“萨利纳斯鲸鱼博物馆”馆藏的搁浅海豚身上获取的38份样本，（iii）来自GenBank的549个线粒体DNA控制区（mtDNA CR）序列，以及（iv）从GenBank中可获得的有丝分裂基因组获得的7个线粒体DNA区域（16S rRNA、12S rRNA、NADH脱氢酶亚基I-II、细胞色素氧化酶I和II、细胞色素b和CR）的66个串联序列。我们的分析表明，使用mtDNA CR可发现内河口和外河口海豚种群之间以及与其他不同种群之间的种群结构。此外，根据mtDNA CR，内河口宽吻海豚（河口宽吻海豚）种群的遗传多样性水平低于外河口海豚种群。最后，基于mtDNA CR和7个线粒体DNA区域，河口宽吻海豚种群在基因上与其他宽吻海豚种群不同。根据这些结果，我们建议河口宽吻海豚种群应被视为一个独特的谱系。这一海豚种群在该地区面临着各种人为威胁；因此，我们强调其脆弱性，并敦促当局迅速出台管理和保护措施。
