Supporting data for: "A natural mechanism of eukaryotic horizontal gene transfer"

Horizontal gene transfer (HGT) is an important process impacting the evolutionary trajectory of eukaryotic species. Yet to date, the mechanism of HGT among eukaryotes has remained a mystery. Here, we demonstrate that Starships, a newly discovered group of cargo-mobilizing transposable elements, are active vectors of horizontally transferred DNA among eukaryotic species. We find that multiple Starships simultaneously transfer themselves and their cargo within and between fungal genera separated by upwards of 100 million years of evolution. Transferred Starships are recovered in strains with and without selection for particular Starship-encoded phenotypes. Using whole genome sequencing, we exclude alternative hypotheses such as heterokaryosis, parasex or the random uptake of exogenous DNA by showing that only Starship DNA is precisely transferred. Furthermore, we demonstrate that the introduction of the Hephaestus Starship into a new species increases metal resistance due to the genes carried by this element. Between 18-33% of all Starships in our focal genus, Paecilomyces, have evidence of horizontal transfer under natural conditions, including between fungal genera, revealing Starship-mediated HGT to be a widespread and frequent phenomenon across filamentous fungi. This study identifies the first active genetic mechanism for HGT between eukaryotic species.

水平基因转移（Horizontal gene transfer，HGT）是影响真核生物物种演化轨迹的关键过程。然而迄今为止，真核生物间的水平基因转移机制仍是未解之谜。本研究证实，一类新发现的转运货物型转座因子——星舰（Starships）——是真核生物间水平转移DNA的活性载体。研究发现，多个星舰元件可在演化时长超1亿年的真菌属内及属间，同时完成自身及其携带货物的转移。已转移的星舰元件可在对特定星舰编码表型存在选择压力或无选择压力的菌株中被检出。借助全基因组测序，研究团队仅检测到星舰DNA的精准转移，由此排除了异核体现象、准性生殖或外源DNA随机摄取等其他假说。此外，研究证实，将赫菲斯托斯星舰（Hephaestus Starship）引入新物种后，可借助该元件携带的基因提升宿主的金属抗性。在本研究聚焦的模式属——拟青霉属（Paecilomyces）中，所有星舰元件中有18%至33%存在自然条件下的水平转移证据，且转移可发生在不同真菌属之间，这表明星舰介导的水平基因转移在丝状真菌中是广泛且高频发生的现象。本研究首次明确了真核生物间水平基因转移的活性遗传机制。