Abstract The brown algae (Phaeophyceae) are a group of multicellular heterokonts that are ubiquitous in today’s oceans. Large brown algae from multiple orders are the foundation to temperate coastal ecosystems globally, a role that extends into arctic and tropical regions, providing services indirectly through increased coastal productivity and habitat provisioning, and directly as a source of food and commercially important extracts. Recent multi-locus and genome-scale analyses have revolutionized our understanding of the brown algal phylogeny, providing a robust framework to test evolutionary hypotheses and interpret genomic variation across diverse brown algal lineages. Here, we review recent developments in our understanding of brown algal evolution based on modern advances in phylogenetics and functional genomics. We begin by summarizing modern phylogenetic hypotheses, illuminating the timescales over which the various brown algal orders diversified. We then discuss key insights on our understanding of brown algal life cycle variation and sexual reproduction systems derived from modern genomic techniques. We also review brown algal speciation mechanisms and the associated biogeographic patterns that have emerged globally. We conclude our review by discussing promising avenues for future research opened by genomic datasets, directions that are expected to reveal critical insights into brown algal evolution in past, present, and future oceans.

中文翻译：

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褐藻的系统发育和进化

摘要 褐藻（Phaeophyceae）是当今海洋中普遍存在的一组多细胞异质生物。来自多个订单的大型褐藻是全球温带沿海生态系统的基础，这一作用延伸到北极和热带地区，通过提高沿海生产力和栖息地供应间接提供服务，并直接作为食物和商业上重要的提取物的来源。最近的多位点和基因组规模分析彻底改变了我们对褐藻系统发育的理解，提供了一个强大的框架来测试进化假设和解释不同褐藻谱系的基因组变异。在这里，我们根据系统发育学和功能基因组学的现代进展回顾了我们对褐藻进化的理解的最新进展。我们首先总结现代系统发育假设，阐明各种褐藻目多样化的时间尺度。然后，我们讨论了关于我们对现代基因组技术衍生的褐藻生命周期变异和有性生殖系统的理解的关键见解。我们还回顾了全球出现的褐藻物种形成机制和相关的生物地理模式。我们通过讨论基因组数据集开辟的未来研究有希望的途径来结束我们的审查，这些方向有望揭示过去、现在和未来海洋中褐藻进化的关键见解。然后，我们讨论了关于我们对现代基因组技术衍生的褐藻生命周期变异和有性生殖系统的理解的关键见解。我们还回顾了全球出现的褐藻物种形成机制和相关的生物地理模式。我们通过讨论基因组数据集开辟的未来研究有希望的途径来结束我们的审查，这些方向有望揭示过去、现在和未来海洋中褐藻进化的关键见解。然后，我们讨论了关于我们对源自现代基因组技术的褐藻生命周期变异和有性生殖系统的理解的关键见解。我们还回顾了全球出现的褐藻物种形成机制和相关的生物地理模式。我们通过讨论基因组数据集开辟的未来研究有希望的途径来结束我们的审查，这些方向有望揭示过去、现在和未来海洋中褐藻进化的关键见解。