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US lifts TikTok federal-device ban, highlighting platform’s enduring US appeal: expert_我的网站
A | “每一个基因组都讲述了一个不同的故事，”共同作者、佛罗里达自然历史博物馆的杰出教授Doug Soltis说。“蕨类植物是所有种子植物最接近的活体近亲，它们对食草动物产生化学威慑，可能对农业研究有用。
The Trump administration has formally lifted restrictions on the use of TikTok on US federal government devices following the restructuring of the platform's US operations, marking another step toward normalizing TikTok’s operations in the US. Analysts said TikTok's continued operation in the country after years of political and regulatory pressure reflects its deep reach among American users and businesses, as well as the competitiveness of Chinese-developed digital products.
The White House Office of Management and Budget said in a memorandum dated Monday and released Tuesday that TikTok is no longer covered by a federal ban on its use on government devices, effectively lifting a restriction imposed over "national security" concerns tied to the platform's previous ownership by ByteDance.
The decision was based on a legal opinion issued by the US Justice Department in July, which concluded that the version of TikTok now operated by the restructured US joint venture, or TikTok USDS Joint Venture, no longer falls under the 2022 federal government-device ban. The opinion also made clear that individual agencies still retain discretion over whether to allow employees to use the app on official devices.
TikTok's ability to remain in the US market after years of political and regulatory pressure demonstrates its strong user appeal and commercial importance, Li Yong, an executive council member of the China Society for WTO Studies, told the Global Times on Wednesday. The platform has become deeply embedded in the US digital economy, with American creators and businesses relying on it to reach audiences, generate income and promote their products, he said.
Its continued operation also reflects the broader global competitiveness of Chinese-developed digital products, Li noted. "Despite years of pressure, TikTok has preserved its core functions, business model and value as a global platform, showing that the appeal of a competitive product cannot simply be erased through political or regulatory restrictions," he said.
Any politically driven move targeting companies of a particular country risks eroding foreign companies' confidence in the US market, and ultimately weakening the country's appeal as a stable and predictable destination for global business, the expert said.
TikTok is used by about 170 million Americans, according to the White House, which noted that content creators rely on the platform for their livelihoods and businesses use it to advertise and connect with customers.
Agencies including the Treasury, Transportation and Health and Human Services departments launched TikTok accounts following the Justice Department's July opinion, while the White House had already created an account last year, according to Politico.
In 2022, the US Congress passed the No TikTok on Government Devices Act, barring TikTok from federal government devices, with several states later following suit. The pressure escalated in 2024, when Congress required ByteDance to divest control of the platform or face a US ban. TikTok briefly went dark in January 2025 before President Donald Trump delayed enforcement while a divestiture deal was negotiated.
The restructuring was completed in January 2026 with the establishment of TikTok USDS Joint Venture. According to the company's official announcement, ByteDance retains a 19.9-percent stake, while the rest is held by investors including Oracle, Silver Lake and MGX.
Under the new structure, the joint venture oversees US user data, algorithm security, content moderation and software assurance. Meanwhile, TikTok has retained global product interoperability, with TikTok global's US entities continuing to manage certain commercial activities, including e-commerce, advertising and marketing, according to the company.
During the China-US economic and trade talks in Madrid, Spain in September 2025, the two sides reached a basic framework consensus on properly resolving the TikTok issue through cooperation, reducing investment barriers and promoting relevant economic and trade cooperation, according to China's Ministry of Commerce (MOFCOM).
A MOFCOM statement said that the Chinese government fully respects companies' wishes and supports them in conducting equal-footed commercial negotiations based on market principles. China will also review matters involving TikTok's technology exports and intellectual property licensing in accordance with the law.
China urged the US to provide a fair, open, transparent, and non-discriminatory business environment for the continuous and stable operation of Chinese enterprises in the US, so as to promote the stable, healthy, and sustainable development of China-US economic and trade relations, a MOFCOM spokesperson said in December, commenting on the reported agreements to establish TikTok's US joint venture.
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B | 然而直到现在，它们仍然是绿色生命中最后一个没有基因组序列的主要品系。”最近，两个不同的研究小组独立发表了桫椤（Alsophila spinulosa）和模式蕨类水蕨（Ceratopteris richardii）的基因组。Ceratopteris的基因组分析为回答为什么蕨类植物平均储存的DNA比其他植物多这一长期的难题提供了提示。与其他物种的基因组比较发现，蕨类植物从细菌那里“偷取”了它们的一些抗草食性毒素的基因。自20世纪60年代以来，人们对蕨类植物含有如此多的DNA最青睐的解释是全基因组的猖獗复制，即意外地将一组额外的染色体传给一个生物体的后代。这有时是有益的，因为所有额外的基因可以作为新性状进化的原材料。事实上，全基因组复制被认为与几乎所有农作物的起源有关。全基因组复制在植物甚至一些动物中都很常见，但大多数生物往往会随着时间的推移抛弃多余的基因包袱，瘦身为更小的基因组，在代谢上更容易维持。斯坦福大学的博士后学者、前佛罗里达博物馆的研究生Blaine Marchant说：“在过去的半个世纪里，这一直是一个主要的讨论点，并导致了各种矛盾的结果。
C | 试图弄清这一悖论背后的进化过程是令人难以置信的重要。”有了第一个完全组装的同胞蕨类基因组，科学家们终于准备好解决这个问题，但要做到这一点并不容易。对Ceratopteris庞大而复杂的基因组进行测序花费了八年多的时间，来自世界各地28个机构的数十名研究人员共同努力，其中包括美国能源部联合基因组研究所。
D | 最后的结果是7.46 gigabases的DNA，是人类基因组的两倍多。如果Ceratopteris通过反复的基因组复制事件增加了DNA，研究人员预计其39对染色体中的大部分将是相同的。但他们发现的是一个混合的重复序列和数以百万计的被称为跳跃基因的短片段，它们占了蕨类植物DNA的85%。与其说是多个基因组副本，不如说Ceratopteris主要包含了数百万年来积累的基因碎片。
E | “功能基因被大量的重复性DNA分开。虽然我们还不确定Ceratopteris和其他蕨类植物的基因组是如何变得如此之大的，但很明显，关于基因组重复发作的普遍观点并没有得到支持，”共同作者、佛罗里达博物馆馆长和杰出教授Pam Soltis说。
F | 作者指出，现在做出任何确定的结论还为时过早，特别是由于这是在这个群体中进行的第一个范围的分析。与其他蕨类植物基因组的交叉比较将有助于更清楚地描绘出这些植物的进化过程。
G | Marchant说，尽管如此，这些结果表明，与几乎所有其他植物相比，具同形孢子蕨类植物管理其遗传内容的方式有明显的区别。“我们似乎发现，像开花植物这样的东西，它们的基因组平均比蕨类植物小得多，只是更擅长摆脱垃圾DNA。它们更善于丢掉多余的染色体，甚至在小规模复制后缩小规模。”仔细观察Ceratopteris内部的数十亿个DNA碱基对，发现有多个防御基因为一种特别险恶的成孔毒素编码。这些毒素与细胞结合，在那里它们被激活并形成小的空心环，冲进细胞膜。水通过产生的孔洞涌入细胞，导致细胞破裂。Marchant解释说，科学家们对形成孔洞的毒素进行了深入研究，因为它们可能用于纳米孔技术。然而，最常见的是，它们在细菌中被发现。Marchant说："这是蕨类植物DNA中这些细菌毒素相关基因的第一个具体证据，"他指出，这种相似性并不是一个巧合。蕨类植物似乎没有自己进化出这种毒素，而是通过一种叫做水平基因转移的过程直接从细菌那里获得了这种毒素。鉴于该基因有多个副本分布在三个独立的染色体上，这很可能发生了不止一次。他说：“令人着迷的是，这些基因的许多拷贝出现在植物的不同部位。一些在茎和根中高度表达，而其他拷贝只在叶子中表达，还有一些一般在所有组织中表达。我们目前不能确定这些基因的确切功能，但它们与细菌中的毒素形成基因的相似性肯定表明这些基因与防御有关。”这不会是蕨类植物第一次将外来DNA纳入其基因组。2014年的一项研究表明，蕨类植物可能是通过借用远缘植物的基因而进化出它们在阴暗环境中生长的特征能力。
H | 然而，相隔数百万年的进化的生物体究竟如何能够交换全功能的基因，仍然不清楚。Doug Soltis解释说：“水平基因转移背后的机制仍然是陆地植物进化中调查最少的领域之一。在进化的时间尺度上，这有点像中彩票。任何时候植物受伤，其内部都容易受到微生物的入侵，但它们的DNA被纳入基因组似乎很神奇。”作者说，这只是一系列研究中的第一步，其实际应用范围从开发新型生物杀虫剂到创新的新保护战略等。
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