Woronowicz Katherine C, Esin Evgeny V, Markevich Grigorii N, Martinez Crisvely Soto, McMenamin Sarah K, Daane Jacob M, Harris Matthew P, Shkil Fedor N
Department of Orthopaedics, Boston Children's Hospital and Department of Genetics, Harvard Medical School, Boston, MA 02115.
AN Severtsov Institute of Ecology and Evolution, RAS; Leninskiy-33, 119071 Moscow, Russian Federation.
bioRxiv. 2024 Apr 27:2023.02.24.529919. doi: 10.1101/2023.02.24.529919.
Recent adaptive radiations provide evolutionary case studies, which provide the context to parse the relationship between genomic variation and the origins of distinct phenotypes. Sympatric radiations of the charr complex (genus ) present a trove for phylogenetics as charrs have repeatedly diversified into multiple morphs with distinct feeding specializations. However, species flocks normally comprise only two to three lineages. Dolly Varden charr inhabiting Lake Kronotske represent the most extensive radiation described for the charr genus, containing at least seven lineages, each with defining morphological and ecological traits. Here, we perform the first genome-wide analysis of this species flock to parse the foundations of adaptive change. Our data support distinct, reproductively isolated lineages with little evidence of hybridization. We also find that specific selection on thyroid signaling and craniofacial genes forms a genomic basis for the radiation. Thyroid hormone is further implicated in subsequent lineage partitioning events. These results delineate a clear genetic basis for the diversification of specialized lineages, and highlight the role of developmental mechanisms in shaping the forms generated during adaptive radiation.
近期的适应性辐射提供了进化案例研究，为解析基因组变异与不同表型起源之间的关系提供了背景。嘉鱼复合体（属）的同域辐射为系统发育学提供了丰富资源，因为嘉鱼多次分化为具有不同摄食特化的多种形态。然而，物种集群通常仅由两到三个谱系组成。栖息在克罗诺茨克湖的花羔红点鲑代表了嘉鱼属中描述的最广泛的辐射，包含至少七个谱系，每个谱系都有明确的形态和生态特征。在此，我们对这个物种集群进行了首次全基因组分析，以解析适应性变化的基础。我们的数据支持不同的、生殖隔离的谱系，几乎没有杂交的证据。我们还发现，对甲状腺信号传导和颅面基因的特定选择构成了辐射的基因组基础。甲状腺激素进一步参与了随后的谱系分化事件。这些结果为特化谱系的多样化描绘了清晰的遗传基础，并突出了发育机制在塑造适应性辐射过程中产生的形态方面的作用。
