Abstract

The extent that Pleistocene climate variability promoted speciation has been much debated. Here, we surveyed genetic markers in winged kelp Alaria in the Gulf of Alaska, Northeast Pacific Ocean to understand how paleoclimates may have influenced diversity in this kelp. The study included wide geographic sampling over 2800 km and large sample sizes compared to previous studies of this kelp. Mitochondrial 5′-COI (664 bp), plastid rbcL-3′ (740 bp) and 8 microsatellite markers in 16 populations resolved 5 well-defined lineages. COI-rbcL haplotypes were distributed chaotically among populations around the Gulf of Alaska. Principal Coordinates Analysis of microsatellite genotypes grouped plants largely by organellar lineage instead of geography, indicating reproductive isolation among lineages. However, microsatellite markers detected hybrids at 3 sites where lineages co-occurred. Local adaptation on various time scales may be responsible for some genetic differences between populations located along wave-energy and salinity gradients, but the chaotic pattern of variability over hundreds of kilometers is likely due to isolations in northern refugia during Pleistocene ice ages. The range of divergences between populations indicates that episodic glaciations led to the creation of new lineages, but population turnover (local extinctions and recolonizations) limited the formation of new species in the Northeastern Pacific Ocean.

中文翻译：

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更新世冰河时代创造了新的进化谱系，但东北太平洋有翅海带的物种形成有限

摘要

更新世气候变率促进物种形成的程度一直备受争议。在这里，我们调查了阿拉斯加湾东北太平洋的带翅海带Alaria 的遗传标记，以了解古气候如何影响这种海带的多样性。该研究包括超过 2800 公里的广泛地理采样和与之前对这种海带的研究相比的大样本量。线粒体 5'- COI（664 bp）、质体rbc L-3'（740 bp）和 16 个种群中的 8 个微卫星标记解析了 5 个明确定义的谱系。COI -红细胞L 单倍型在阿拉斯加湾周围的人群中分布混乱。微卫星基因型的主要坐标分析主要按细胞器谱系而不是地理对植物进行分组，表明谱系之间存在生殖隔离。然而，微卫星标记在谱系共存的 3 个位点检测到杂种。不同时间尺度上的局部适应可能是造成沿波能和盐度梯度分布的种群之间存在一些遗传差异的原因，但数百公里范围内变化的混乱模式可能是由于更新世冰河时代北部避难所的隔离造成的。种群之间的差异范围表明，偶发性冰川作用导致了新谱系的产生，