Mueller Rebecca, Wright Jeffrey T, Bolch Christopher J S
Institute for Marine and Antarctic Studies, University of Tasmania, Private Bag 1370, Launceston, Tasmania, 7250, Australia.
J Phycol. 2018 Feb;54(1):56-65. doi: 10.1111/jpy.12599. Epub 2017 Nov 13.
The palaeoceanography of southern Australia has been characterized by fluctuating sea levels during glacial periods, changing temperature regimes and modified boundary currents. Previous studies on genetic structuring of species in southeastern Australia have focused mainly on the differentiation of eastern and western populations while the potential role of Bass Strait as a region of overlap for three biogeographic provinces (Peronia, Maugea, and Flindersia) has been largely ignored. This study aimed to explore the likely roles of historic and contemporary factors in determining divergence patterns in the habitat-forming intertidal seaweed Hormosira banksii in southeastern Australia with a special focus on postglacial dispersal into Bass Strait. We examined the genetic diversity of 475 Hormosira specimens collected from 19 sites around southern Australia using DNA sequence analysis of cytochrome oxidase 1. Three major haplotype groups were identified (western, centre and eastern) corresponding with the three existing biogeographical provinces in this region. Historic break points appeared to be retained and reinforced by modern day dispersal barriers. Phylogeographic grouping of Hormosira reflected a combination of historic and contemporary oceanography. As western and eastern group haplotypes were largely absent within Bass Strait, re-colonization after the last glacial maximum appeared to have originated from refuges within or near present day Bass Strait. Patterns of genetic structure for Hormosira are consistent with other marine species in this region and highlight the importance of biogeographical barriers in contributing to modern genetic structure.
澳大利亚南部的古海洋学特征表现为冰川期海平面波动、温度变化以及边界流改变。此前关于澳大利亚东南部物种遗传结构的研究主要集中在东部和西部种群的分化上，而巴斯海峡作为三个生物地理省份（佩罗尼亚、毛盖亚和弗林德斯亚）重叠区域的潜在作用在很大程度上被忽视了。本研究旨在探讨历史和当代因素在决定澳大利亚东南部形成栖息地的潮间带海藻——班氏 Hormosira 分歧模式中可能发挥的作用，特别关注末次冰盛期后向巴斯海峡的扩散。我们使用细胞色素氧化酶 1 的 DNA 序列分析，检测了从澳大利亚南部 19 个地点采集的 475 个 Hormosira 标本的遗传多样性。确定了三个主要单倍型组（西部、中部和东部），与该地区现有的三个生物地理省份相对应。历史断点似乎因现代扩散障碍而得以保留和强化。Hormosira 的系统地理学分组反映了历史和当代海洋学的综合影响。由于巴斯海峡内基本没有西部和东部组的单倍型，末次冰盛期后的重新定殖似乎起源于现今巴斯海峡内或附近的避难所。Hormosira 的遗传结构模式与该地区的其他海洋物种一致，并突出了生物地理屏障在塑造现代遗传结构中的重要性。
