Department of Biology, University of Alabama at Birmingham, 1300 University Blvd, Birmingham, Alabama, 35294, USA.
Odum School of Ecology, University of Georgia, 140 E. Green St., Athens, Georgia, 30602, USA.
J Phycol. 2021 Oct;57(5):1403-1410. doi: 10.1111/jpy.13195. Epub 2021 Jul 22.
Single-gene markers, such as the mitochondrial cox1, microsatellites, and single-nucleotide polymorphisms are powerful methods to describe diversity within and among taxonomic groups and characterize phylogeographic patterns. Large repositories of publicly-available, molecular data can be combined to generate and evaluate evolutionary hypotheses for many species, including algae. In the case of biological invasions, the combination of different molecular markers has enabled the description of the geographic distribution of invasive lineages. Here, we review the phylogeography of the widespread invasive red macroalga Agarophyton vermiculophyllum (synonym Gracilaria vermiculophylla). The cox1 barcoding provided the first description of the invasion history and hinted at a strong genetic bottleneck during the invasion. Yet, more recent microsatellite and SNP genotyping has not found evidence for bottlenecks and instead suggested that genetically diverse inocula arose from a highly diverse source population, multiple invasions, or some mix of these processes. The bottleneck evident from cox1 barcoding likely reflects the dominance of one mitochondrial lineage, and one haplotype in particular, in the northern source populations in Japan. Recent cox1 sequencing of A. vermiculophyllum has illuminated the complexity of phylogeographic structure in its native range of the northwest Pacific Ocean. For example, the western coast of Honshu in the Sea of Japan displays spatial patterns of haplotypic diversity with multiple lineages found together at the same geographic site. By consolidating the genetic data of this species, we clarify the phylogenetic relationships of a well-studied macroalga introduced to virtually every temperate estuary of the Northern Hemisphere.
单基因标记，如线粒体 cox1、微卫星和单核苷酸多态性，是描述分类群内和分类群间多样性以及表征系统地理格局的有力方法。大量公开可用的分子数据存储库可以组合在一起，为许多物种（包括藻类）生成和评估进化假说。在生物入侵的情况下，不同分子标记的结合使入侵谱系的地理分布得以描述。在这里，我们回顾了广泛分布的入侵性红藻 Agarophyton vermiculophyllum（同义词 Gracilaria vermiculophylla）的系统地理学。cox1 条形码提供了入侵历史的首次描述，并暗示在入侵过程中存在强烈的遗传瓶颈。然而，最近的微卫星和 SNP 基因分型并没有发现瓶颈的证据，而是表明遗传上多样化的接种物源自高度多样化的源种群、多次入侵，或这些过程的某种混合。cox1 条形码中明显的瓶颈可能反映了在日本北部源种群中一种线粒体谱系和一种特定单倍型的优势。最近对 Agarophyton vermiculophyllum 的 cox1 测序揭示了其在西北太平洋本土范围内系统地理结构的复杂性。例如，日本海的本州西海岸显示出单倍型多样性的空间格局，多个谱系在同一地理地点同时出现。通过整合该物种的遗传数据，我们澄清了引入到北半球几乎每个温带河口的研究充分的大型藻类的系统发育关系。
