Dipartimento di Scienze della Vita e dell'Ambiente, Università Politecnica delle Marche, Via Brecce Bianche, Ancona, 60131, Italy.
School of BioSciences, University of Melbourne, Victoria, 3010, Australia.
J Phycol. 2020 Aug;56(4):1109-1113. doi: 10.1111/jpy.13006. Epub 2020 May 22.
Populations of many Mediterranean marine species show a strong phylogeographic structure, but the knowledge available for native seaweeds is limited. We investigated the genetic diversity of the green alga Halimeda tuna based on two plastid markers (tufA gene and a newly developed amplicon spanning five ribosomal protein genes and intergenic spacers, the rpl2-rpl14 region). The tufA sequences showed that Mediterranean H. tuna represents a single, well-defined species. The rpl2-rpl14 results highlighted a genetic separation between western and eastern Mediterranean populations; specimens collected from widely scattered locations in the Adriatic/Ionian region shared a haplotype unique to this region, and formed a group separated from all western Mediterranean regions. Specimens from Sardinia also formed a unique haplotype. Within the western Mediterranean basin, a gradual shift in the frequency of haplotypes was apparent along a West-East gradient. Our results represent the first clear evidence of an East-West genetic cleavage in a native Mediterranean macroalga and offer an interesting perspective for further research into fine-scale seaweed population structure in the NW Mediterranean Sea.
许多地中海海洋物种的种群表现出强烈的系统地理学结构，但有关本地海藻的知识有限。我们基于两个质体标记（tufA 基因和一个新开发的扩增子，跨越五个核糖体蛋白基因和基因间间隔区，rpl2-rpl14 区域）研究了绿藻 Halimeda tuna 的遗传多样性。tufA 序列表明，地中海 H. tuna 代表一个单一的、明确界定的物种。rpl2-rpl14 的结果突出了东西地中海种群之间的遗传分离；从亚得里亚海/爱奥尼亚地区广泛分布的地点采集的标本共享该地区特有的单倍型，并与所有西地中海地区分离。来自撒丁岛的标本也形成了一个独特的单倍型。在西地中海盆地内，单倍型的频率沿着西-东梯度明显变化。我们的结果首次提供了在地中海本地大型海藻中存在东西向遗传分裂的明确证据，并为进一步研究西北地中海海域的细尺度海藻种群结构提供了有趣的视角。
