牛曾是香港农民的劳作动物，但经济条件的变化最终导致养牛业衰落。随后，在20世纪70年代，一些牛被遗弃，开始自由漫游。数代之后，这些动物已成为一个独特的野化种群，生活在很少受到塑造家养牛的那种人类管理之下。现在，它们的DNA正在揭示这一变化之后发生了什么。一项2026年的基因组研究对30头香港野化牛进行了测序，并将其与四个主要种群的116头牛进行了比较。
Cattle once served as working animals for farmers in Hong Kong, but changing economic conditions eventually led to the decline of cattle farming. Then, in the 1970s, some cattle were abandoned and began roaming freely. Generations later, the animals have become a distinctive feral population, living with little of the human management that shaped domestic cattle. Now, their DNA is offering clues to what happened after that change. A 2026 genome study sequenced 30 Hong Kong feral cattle and compared them with 116 cattle from four major populations.
结果显示，这个种群尽管规模不大，却保留了出乎意料的高水平遗传多样性，同时也携带着与其长期隔离史、古老野牛祖先以及对当地环境适应相关的基因标记。当牛不再遵循人类规则据认为，香港牛群的数量约为1000头。研究人员主要从西贡、大屿岛以及新界东部和北部采集了样本。与传统家畜不同，这些动物在面临环境压力时，并未得到通常提供给农场牛的同等程度的保护、受控繁殖和兽医护理。
The results revealed a population that retained surprisingly high genetic diversity despite its small size, while also carrying genetic signatures linked to its long history of isolation, ancient wild-bovine ancestry and adaptation to the local environment. When cattle stopped living by human rulesThe Hong Kong cattle population is thought to number about 1,000 animals. Researchers collected samples mainly from Sai Kung, Lantau Island, and the eastern and northern New Territories. Unlike conventional livestock, these animals have faced environmental pressures without the same level of protection, controlled breeding, and veterinary care normally provided to farm cattle.
这使得该种群对于研究家养动物野化后会发生什么，具有异常重要的价值。一项2020年的研究已经发现，香港牛在基因上具有独特性，并显示出与野牛有关的祖先证据。那项早期研究检查了21头香港牛，以及代表36个牛群和包括印度野牛和爪哇野牛在内的野生物种的703头动物。在新研究中，分析更为广泛，因为它检查了每只动物的完整基因组，而非主要关注选定的遗传标记。
That makes the population unusually valuable for studying what happens when domesticated animals become feral. A 2020 study had already found that Hong Kong cattle were genetically distinctive and showed evidence of ancestry connected with wild bovines. That earlier work examined 21 Hong Kong cattle alongside 703 animals representing 36 cattle populations and wild species including gaur and banteng. In the new research, the analysis was more extensive because it examined each animal’s full genome rather than focusing mainly on selected genetic markers.
研究团队以 30 倍覆盖深度对这 30 头牛的基因组进行了测序。牛的 DNA 揭示了什么？全基因组分析显示，香港牛与东亚瘤牛（indicine cattle）的亲缘关系最近，尽管该种群已形成独有的遗传特征。科学家还发现，在与其他东亚瘤牛分化之前，香港牛的祖先曾从爪哇野牛（banteng）和野牛（gaur）那里获得过一些基因输入。
The team sequenced the genomes of the 30 animals at 30x coverage depth. What does the cattle DNA reveal? Genome-wide analysis revealed that Hong Kong cattle were most closely related to East Asian indicine cattle, although the population has developed a genetic signature unique to itself. Scientists also found that the cattle's ancestors received some genetic input from banteng and gaur before diverging from other East Asian indicine cattle.
更有趣的是这一事件发生的时间。爪哇野牛的基因渗入大约发生在 8900 年前，而野牛的基因渗入则发生在约 9900 年前。换句话说，如今野化牛体内的某些基因，可能早在它们在香港变成独立种群之前很久就已进入其谱系。
Even more interesting is when this happened. It appears that the banteng introgression took place approximately 8,900 years ago, while gaur introgression occurred about 9,900 years ago. In other words, some of the genes in today’s feral cattle may have entered the lineage long before the animals became independent in Hong Kong.
这些牛表现出高遗传多样性与近亲繁殖并存的异常组合。尽管有效种群规模减小，它们仍保持了较高的基因组变异。此外，与其他几个瘤牛种群相比，这些牛显示出更长的同源 DNA 片段。野外生活是如何塑造它们的？
The cattle showed an unusual combination of high genetic diversity and inbreeding. Despite having decreased effective population size, the cattle still maintained high genomic variation. On top of that, these cattle displayed longer segments of the same DNA sequence than several other indicine populations. How did life in the wild shape them?
研究人员随后通过检测某些基因组区域在适应环境过程中是否受到青睐，来寻找自然选择的证据。部分基因组区域显示出与生存相关性状的关联，例如耐热性、骨密度和被毛色素沉着。ADRA1A 基因的一个特定基因组区域显示出与热应激反应的关联。其他基因组区域则显示出与发育、免疫和代谢相关生物功能的关联。
The investigators then looked for evidence of natural selection by testing whether certain genome regions were favored during adaptation to the cattle’s environment. Some genomic regions showed associations with traits relevant to survival, such as heat resistance, bone density, and coat pigmentation. A specific genomic region for the ADRA1A gene showed an association with heat stress response. Other genomic regions showed associations with biological functions related to development, immunity, and metabolism.
牛的外貌特征提供了另一条线索。香港的野化牛呈现出多样的毛色花纹、独特的角形、不对称的驼峰以及不规则的体型轮廓。研究团队在 NINL、DEXI 和 CIITA 等基因中发现了拷贝数变异，这可能有助于解释被毛颜色的差异。
The cattle’s physical appearance is another clue. The feral cattle in Hong Kong come in displaying varied fur patterns, distinct horn shapes, asymmetrical humps, and irregular body profiles. The research team found copy-number variation in genes such as NINL, DEXI, and CIITA that may help explain differences in coat color.
然而，研究结果并不意味着所有基因差异都已被确认为适应性特征。研究人员列出了其中几个基因区域作为候选对象，其效应仍需进一步检验。2026年，DNA结果讲述了一个更宏大的故事，揭示了几代祖先血统、隔离和自然选择如何塑造了这一种群。该牛群提供了一个罕见的例子，展示了家养动物在人类影响消退后如何进化。
However, the results of the research do not mean that all genetic differences have been confirmed as adaptations. The researchers listed a few of these gene regions as candidates whose effects still need to be tested. In 2026, the DNA results tell a broader story about how generations of ancestry, isolation, and natural selection shaped the population. The herd offers a rare example of how domesticated animals evolve when human influence fades.
对科学家而言，该牛群远不止是一个有趣的基因研究课题。该牛群的野牛血统、高遗传多样性及表现出的适应性，有助于科学家研究高温、疾病及其他压力如何塑造牛的进化。对香港而言，这群游荡的牛群是该地区农业历史的活见证。
For scientists, the herd is much more than an interesting subject of genetic research. The herd’s wild-bovine ancestry, high genetic diversity, and apparent adaptation could help scientists study how heat, disease, and other pressures shape cattle evolution. For Hong Kong, the wandering herd is a living reminder of the territory’s agricultural history.