Guerrero-Jiménez Claudia Jimena, Peña Fabiola, Morales Pamela, Méndez Marco, Sallaberry Michel, Vila Irma, Poulin Elie
Departamento de Ciencias Ecológicas, Facultad de Ciencias, Universidad de Chile, Ñuñoa, Santiago, Región Metropolitana, Chile.
Escuela de Medicina Veterinaria, Facultad de Recursos Naturales y Medicina Veterinaria, Universidad Santo Tomás, Talca, Región del Maule Chile.
PLoS One. 2017 Feb 28;12(2):e0170380. doi: 10.1371/journal.pone.0170380. eCollection 2017.
During the Pleistocene and Holocene, the southwest Andean Altiplano (17°-22°S) was affected by repeated fluctuations in water levels, high volcanic activity and major tectonic movements. In the early Holocene the humid Tauca phase shifted to the arid conditions that have lasted until the present, producing endorheic rivers, lakes, lagoons and wetlands. The endemic fish Orestias (Cyprinodontidae) represents a good model to observe the genetic differentiation that characterizes an incipient speciation process in allopatry since the morphospecies described inhabit a restricted geographic area, with present habitat fragmentation. The genetic diversity and population structure of four endemic morphospecies of Orestias (Cyprinodontidae) found in the Lauca National Park (LNP) analyzed with mitochondrial markers (Control Region) and eight microsatellites, revealed the existence of genetic groups that matches the fragmentation of these systems. High values of genetic and phylogeographic differentiation indices were observed between Chungará Lake and Piacota lagoon. The group composed of the Lauca River, Copapujo and Chuviri wetlands sampling sites showed a clear signal of expansion, with a star-like haplotype network. Levels of genetic differentiation were lower than in Chungará and Piacota, suggesting that these localities would have differentiated after the bottlenecks linked to the collapse of Parinacota volcano. The Parinacota sample showed a population signal that differed from the other localities revealing greater genetic diversity and a disperse network, presenting haplotypes shared with other LNP localities. A mixing pattern of the different genetic groups was evident using the microsatellite markers. The chronology of the vicariance events in LNP may indicate that the partition process of the Orestias populations was gradual. Considering this, and in view of the genetic results, we may conclude that the morphospecies from LNP are populations in ongoing differentiation process.
在更新世和全新世期间，安第斯山脉西南部的高原（南纬17° - 22°）受到水位反复波动、高火山活动和重大构造运动的影响。在全新世早期，湿润的陶卡期转变为持续至今的干旱条件，形成了内流河、湖泊、泻湖和湿地。特有鱼类奥雷斯提亚属（鲤齿鳉科）是一个很好的模型，可用于观察异地初始物种形成过程中典型的遗传分化，因为所描述的形态物种栖息在一个受限的地理区域，且目前栖息地碎片化。利用线粒体标记（控制区）和八个微卫星对在劳卡国家公园（LNP）发现的四种奥雷斯提亚属（鲤齿鳉科）特有形态物种的遗传多样性和种群结构进行分析，结果显示存在与这些系统碎片化相匹配的遗传群体。在钦加拉湖和皮亚科塔泻湖之间观察到高值的遗传和系统地理学分化指数。由劳卡河、科帕普霍和丘维里湿地采样点组成的群体显示出明显的扩张信号，单倍型网络呈星状。遗传分化水平低于钦加拉和皮亚科塔，这表明这些地区在与帕里纳科塔火山崩塌相关的瓶颈事件之后才出现分化。帕里纳科塔样本显示出与其他地区不同的种群信号，揭示出更大的遗传多样性和分散的网络，呈现出与其他LNP地区共享的单倍型。使用微卫星标记时，不同遗传群体的混合模式很明显。LNP地区的地理隔离事件年代表明，奥雷斯提亚种群的分隔过程可能是渐进的。考虑到这一点，并鉴于遗传结果，我们可以得出结论，来自LNP的形态物种正处于持续分化的种群阶段。
