Lesturgie Pierre, Braun Camrin D, Clua Eric, Mourier Johann, Thorrold Simon R, Vignaud Thomas, Planes Serge, Mona Stefano
Institut de Systématique, Evolution, Biodiversité (ISYEB), Muséum National d'Histoire Naturelle, EPHE-PSL Université PSL, CNRS, SU, UA Paris France.
Biology Department Woods Hole Oceanographic Institution Woods Hole Massachusetts USA.
Ecol Evol. 2023 Jan 10;13(1):e9746. doi: 10.1002/ece3.9746. eCollection 2023 Jan.
Designing appropriate management plans requires knowledge of both the dispersal ability and what has shaped the current distribution of the species under consideration. Here, we investigated the evolutionary history of the endangered gray reef shark () across its range by sequencing thousands of RADseq loci in 173 individuals in the Indo-Pacific (IP). We first bring evidence of the occurrence of a range expansion (RE) originating close to the Indo-Australian Archipelago (IAA) where two stepping-stone waves (east and westward) colonized almost the entire IP. Coalescent modeling additionally highlighted a homogenous connectivity ( ~ 10 per generation) throughout the range, and isolation by distance model suggested the absence of barriers to dispersal despite the affinity of to coral reefs. This coincides with long-distance swims previously recorded, suggesting that the strong genetic structure at the IP scale ( ~ 0.56 between its ends) is the consequence of its broad current distribution and organization in a large number of demes. Our results strongly suggest that management plans for the gray reef shark should be designed on a range-wide rather than a local scale due to its continuous genetic structure. We further contrasted these results with those obtained previously for the sympatric but strictly lagoon-associated , known for its restricted dispersal ability. exhibits a similar RE dynamic but is characterized by a stronger genetic structure and a nonhomogeneous connectivity largely dependent on local coral reefs availability. This sheds new light on shark evolution, emphasizing the roles of IAA as source of biodiversity and of life-history traits in shaping the extent of genetic structure and diversity.
设计合适的管理计划需要了解物种的扩散能力以及影响当前所考虑物种分布的因素。在此，我们通过对印度 - 太平洋地区（IP）173个个体的数千个RADseq基因座进行测序，研究了濒危灰礁鲨（）在其分布范围内的进化历史。我们首先提供了证据，证明其分布范围扩张（RE）起源于印度 - 澳大利亚群岛（IAA）附近，在此有两个踏脚石式的扩散波（向东和向西）几乎殖民了整个IP地区。溯祖模型还突出显示了整个分布范围内均匀的连通性（每代约为10），距离隔离模型表明尽管与珊瑚礁有亲和力，但不存在扩散障碍。这与先前记录的长途游动相吻合，表明在IP尺度上强大的遗传结构（两端之间约为0.56）是其当前广泛分布和在大量种群中组织的结果。我们的结果强烈表明，由于灰礁鲨具有连续的遗传结构，其管理计划应在整个分布范围内而非局部尺度上进行设计。我们进一步将这些结果与先前针对同域但严格与泻湖相关的 所获得的结果进行对比， 以其有限的扩散能力而闻名。 表现出类似的分布范围扩张动态，但具有更强的遗传结构和很大程度上依赖于当地珊瑚礁可利用性的非均匀连通性。这为鲨鱼进化提供了新的视角，强调了IAA作为生物多样性来源以及生活史特征在塑造遗传结构和多样性程度方面的作用。
