Dang Binh Thuy, Truong Oanh Thi, Tran Sang Quang, Glenner Henrik
Institute for Biotechnology and Environment, Nha Trang University, Nha Trang, Khanh Hoa, Vietnam.
Department of Biological Science, University of Bergen, Bergen, Norway.
PeerJ. 2021 Jul 7;9:e11671. doi: 10.7717/peerj.11671. eCollection 2021.
By comparing spatial geographical structures of host populations with that of their symbionts light can be shed on their biological interactions, and the degree of congruence between host and symbiont phylogeographies should reflect their life histories and especially dispersal mechanisms.
Here, we analyzed the genetic diversity and structure of a host, the blue swimming crab, , and its symbiotic pedunculate barnacle from six location sites representing three geographic regions (north, central and south) along the Vietnam coastline. High levels of congruence in their phylogeographic patterns were expected as they both undergo planktonic larval stages.
Based on the COI mtDNA markers, populations showed higher genetic diversity in comparison with their host (number of haplotype/individuals, haplotype and nucleotide diversity are 119/192, 0.991 ± 0.002 and 0.02; and 89/160, 0.913 ± 0.02 and 0.015, respectively). Pairwise Fst and AMOVA analyses showed a more pronounced population structure in the symbiotic barnacle than in its crab host. The DAPC analyses identified three genetic clusters. However, both haplotype networks and scatter plots supported connectivity of the host and the symbiotic barnacle throughout their distribution range, except for low subdivision of southern population. Isolation by distance were detected only for the symbiont (R = 0.332, = 0.05), while dbMEM supported spatial structure of both partners, but only at MEM-1 (Obs. 0.2686, < 0.01 and Obs. 0.2096, < 0.01, respectively).
通过比较宿主种群与其共生体的空间地理结构，可以揭示它们之间的生物相互作用，宿主和共生体系统地理学之间的一致性程度应反映它们的生活史，尤其是扩散机制。
在这里，我们分析了宿主蓝蟹及其共生有柄藤壶的遗传多样性和结构，样本来自越南海岸线三个地理区域（北部、中部和南部）的六个地点。由于它们都经历浮游幼虫阶段，预计它们的系统地理模式会有高度的一致性。
基于细胞色素氧化酶亚基I（COI）线粒体DNA标记，藤壶种群比其宿主蓝蟹显示出更高的遗传多样性（单倍型数量/个体数量、单倍型多样性和核苷酸多样性分别为119/192、0.991±0.002和0.02；以及89/160、0.913±0.02和0.015）。成对Fst分析和分子方差分析（AMOVA）表明，共生藤壶的种群结构比其蟹宿主更为明显。判别分析（DAPC）确定了三个遗传簇。然而，单倍型网络和散点图都支持宿主和共生藤壶在其整个分布范围内的连通性，除了南部种群的低分化情况。仅在共生体藤壶中检测到距离隔离（R = 0.332，P = 0.05），而距离矩阵多变量空间分析（dbMEM）支持两个共生伙伴的空间结构，但仅在MEM-1水平上（观测值分别为0.2686，P < 0.01和0.2096，P < 0.01）。
