Laboratorio de Ecología Molecular, Departamento de Ciencias Ecológicas, Facultad de Ciencias, Universidad de Chile, Las Palmeras # 3425, Ñuñoa, Santiago, Chile; Instituto de Ecología y Biodiversidad (IEB), Las Palmeras # 3425, Ñuñoa, Santiago, Chile; Pontificia Universidad Católica de Chile, Facultad de Agronomía e Ingeniería Forestal, Departamento de Ecosistemas y Medio Ambiente, Vicuña Mackenna 4860, Macul, Santiago, Chile.
Department of Animal Breeding and Genetics, Swedish University of Agricultural Sciences, Uppsala, Sweden; Facultad de Ciencias Veterinarias y Pecuarias, Universidad de Chile, Santiago 8820808, Chile.
Mol Phylogenet Evol. 2019 Oct;139:106563. doi: 10.1016/j.ympev.2019.106563. Epub 2019 Jul 16.
The study of systematics in wide-ranging seabirds can be challenging due to the vast geographic scales involved, as well as the possible discordance between molecular, morphological and behavioral data. In the Southern Ocean, macaroni penguins (Eudyptes chrysolophus) are distributed over a circumpolar range including populations in Antarctic and sub-Antarctic areas. Macquarie Island, in its relative isolation, is home to a closely related endemic taxon - the royal penguin (Eudyptes schlegeli), which is distinguishable from E. chrysolophus mainly by facial coloration. Although these sister taxa are widely accepted as representing distinct species based on morphological grounds, the extent of their genome-wide differentiation remains uncertain. In this study, we use genome-wide Single Nucleotide Polymorphisms to test genetic differentiation between these geographically isolated taxa and evaluate the main drivers of population structure among breeding colonies of macaroni/royal penguins. Genetic similarity observed between macaroni and royal penguins suggests they constitute a single evolutionary unit. Nevertheless, royal penguins exhibited a tendency to cluster only with macaroni individuals from Kerguelen Island, suggesting that dispersal occurs mainly between these neighboring colonies. A stepping stone model of differentiation of macaroni/royal populations was further supported by a strong pattern of isolation by distance detected across its whole distribution range, possibly driven by large geographic distances between colonies as well as natal philopatry. However, we also detected intraspecific genomic differentiation between Antarctic and sub-Antarctic populations of macaroni penguins, highlighting the role of environmental factors together with geographic distance in the processes of genetic differentiation between Antarctic and sub-Antarctic waters.
对广泛分布的海鸟进行系统学研究可能具有挑战性，因为涉及的地理范围很广，而且分子、形态和行为数据之间可能存在不一致。在南大洋，麦哲伦企鹅（Eudyptes chrysolophus）分布范围广泛，包括南极和亚南极地区的种群。麦夸里岛相对孤立，是一种密切相关的特有分类群——皇家企鹅（Eudyptes schlegeli）的家园，后者主要通过面部颜色与 E. chrysolophus 区分开来。尽管这些姐妹分类群在形态学基础上被广泛认为代表不同的物种，但它们的全基因组分化程度仍不确定。在这项研究中，我们使用全基因组单核苷酸多态性来检验这些地理隔离分类群之间的遗传分化，并评估麦哲伦/皇家企鹅繁殖群体中种群结构的主要驱动因素。麦哲伦和皇家企鹅之间观察到的遗传相似性表明它们构成了一个单一的进化单位。然而，皇家企鹅仅倾向于与来自凯尔盖朗岛的麦哲伦个体聚类，这表明主要在这些相邻的群体之间发生扩散。在整个分布范围内检测到的强烈的隔离距离模式进一步支持了麦哲伦/皇家种群分化的踏脚石模型，这可能是由群体之间的大地理距离以及出生地的亲缘关系所驱动的。然而，我们还检测到麦哲伦企鹅南极和亚南极种群之间的种内基因组分化，突出了环境因素与地理距离一起在南极和亚南极水域遗传分化过程中的作用。
