Data from: Seabird and Louse Coevolution: Complex Histories Revealed by 12S rRNA Sequences and Reconciliation Analyses

We investigated the coevolutionary history of seabirds (orders Procellariiformes and Sphenisciformes) and their lice (order Phthiraptera). Independent trees were produced for the seabirds (tree derived from 12S ribosomal RNA (rRNA), isozyme, and behavioral data) and their lice (trees derived from 12S rRNA data). Brookâ s parsimony analysis (BPA) supported a general history of cospeciation (consistency index = 0.84, retention index = 0.81). We inferred that the homoplasy in the BPA was caused by one intrahost speciation, one potential host switching and eight or nine sorting events. Using reconciliation analysis we quantified the cost of fitting the louse tree onto the seabird tree. The reconciled TreeMap tree postulated one host switching, nine cospeciation, three or four intrahost speciation and 11 to 14 sorting events. The number of cospeciation events was significantly more than would be expected due to chance. The sequence data were used to test for rate heterogeneity for both seabirds and lice. The seabird tree showed no significant rate heterogeneity over all of its branches whereas part of the louse tree did show rate heterogeneity. An examination of the codivergent nodes revealed that seabirds and lice have cospeciated synchronously, and that lice have evolved at about 5.5 times the rate of seabirds. Sequence data supported some of the postulated intrahost speciation events (Halipeurus pre-dated the evolution of their present hosts). Sequence data also supported some of the postulated host-switching events. These results demonstrate the value of sequence data and reconciliation analyses in unraveling complex histories between hosts and their parasites.

本研究针对海鸟（鹱形目Procellariiformes、企鹅目Sphenisciformes）与其羽虱（虱毛目Phthiraptera）的协同演化历史展开了系统探究。研究分别构建了海鸟与羽虱的独立系统发育树：海鸟树基于12S核糖体RNA（12S ribosomal RNA，rRNA）、同工酶及行为学数据构建，羽虱树则基于12S rRNA数据构建。布鲁克斯简约分析（Brooks Parsimony Analysis，BPA）结果显示，整体演化历史符合协同成种模式（一致性指数CI=0.84，保留指数RI=0.81）。经推断，BPA分析中检出的同塑性现象由1次宿主内成种、1次潜在宿主切换以及8至9次谱系分选事件共同导致。本研究通过树比对分析量化了将羽虱系统发育树拟合至海鸟树所需的演化成本，经TreeMap工具生成的比对结果显示，共存在1次宿主切换、9次协同成种事件、3至4次宿主内成种事件以及11至14次谱系分选事件。协同成种事件的数量显著高于随机演化过程的预期值。研究利用序列数据对海鸟与羽虱的演化速率异质性进行了检验：海鸟树的所有分支均未检出显著的演化速率异质性，而羽虱树的部分分支则存在显著速率异质性。对共分化节点的分析显示，海鸟与羽虱的协同成种事件具有同步性，且羽虱的演化速率约为海鸟的5.5倍。序列数据验证了部分假设的宿主内成种事件（如海羽虱属Halipeurus的演化早于其当前宿主的演化历程），同时也支持了部分假设的宿主切换事件。上述研究结果证实了序列数据与树比对分析在解析宿主-寄生虫间复杂协同演化关系中的重要应用价值。