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Wolves living by Chernobyl nuclear plant develop cancer-resistant genes
Wolves living near the Chernobyl nuclear plant have evolved to withstand cancer-causing radiation, scientists believe.
The Chernobyl wolves are exposed to about 11.28 millirem of radiation every day, which is more than six times the legal safety limit for the average human worker.
Evolutionary biologists from Princeton University have been studying blood samples from wolves inside and outside the Chernobyl Exclusion Zone (CEZ) – a 1,000sqm area cleared of human activity after the disaster.
The team found that wolves living in the CEZ had altered immune systems, similar to cancer patients undergoing radiation treatment, as well as genetic changes which seem to protect against cancer.
The team is hoping that the study will eventually identify proactive mutations which could increase the odds of fighting cancer in humans.
The Chernobyl disaster occurred on April 26 1986 with the explosion of reactor number four at the nuclear power plant causing an updraft of radioactivity which spread across Europe.
Two people died immediately and 29 within the coming days of acute radiation syndrome, while the United Nations estimated some 4,000 more died from the fallout.
Many women also aborted their babies for fear they would be affected by radiation poisoning.
However, in recent years, researchers have found that closing off surrounding land to humans has allowed wildlife to flourish, with the area now a haven for lynx, bison, brown bear, wolves, boar and deer as well as 60 rare plant species.
The exclusion zone currently represents the third-largest nature reserve in mainland Europe and is often considered an accidental experiment in rewilding.
Previous studies showed that exposure to radiation speeds up the genetic mutation rate among plants, with some species evolving new chemistry that makes them more resistant to radiation damage and protects their DNA.
Scientists have pointed out that in the past when early plants were evolving, levels of natural radiation on Earth were far higher than now, so species may be able to switch on dormant traits to survive.
However, it was unknown whether the same protective adaptations would be seen in larger animals.
The study was presented at the Society for Integrative and Comparative Biology’s annual meeting in Seattle.
注释：
updraft: n
表示"上升气流"，means "a strong upward air curren"，如：Peak updraft strength is slightly enhanced with hodograph curvature. 山顶上升气流强度随速矢端迹曲率加大而稍有加强。
haven: n
表示"避难所"，means "harbour;place of safety or rest"，如：Terrorists will not find a safe haven here. 恐怖分子在这里将找不到安身之处。
lynx: n
表示" 山猫；猞猁"，如：Lynx is a nationally protected animal. 猞猁是受国家保护的动物。
bison: n
表示"野牛"，如：American bison are very large. 美洲野牛非常巨大。
dormant: adj
表示"休眠的"，means "in a condition of biological rest or suspended animation"，如：Many living things are dormant in winter.很多生物到了冬季都休眠。
中文简要说明：
1986年4月26日，苏联境内的切尔诺贝利（Chernobyl）核电厂发生爆炸，造成大量的放射性物质外泄，成为人类史上最严重的核灾事故。事故发生后，超过15万名居民被迫撤离，核电厂周遭1000平方英里（约2590平方公里）被划为禁区，人类不得活动、居住，也因此成了野生动物的天堂，狼、野牛、野猪、麋鹿和超过200种鸟类在此群居。
然而近年有科学家发现，辐射禁区内的狼群出现基因突变，演化出抵抗辐射致癌的能力，或许可成为人类治疗癌症的新契机。这项研究成果发表于今年1月的「综合与比较生物学学会」（SICB）西雅图年会。
英国《每日邮报》、《每日电讯报》报导，普林斯顿大学演化生物学家洛夫（Cara Love）率领团队前往切尔诺贝利，研究禁区内外的狼群。他们采集狼群血液后发现，尽管暴露的辐射量是核电厂工作人员法定安全值的六倍之多，这些狼却似乎不受影响，它们身上的免疫系统发生基因突变，情况类似于癌症患者接受放射线治疗后的改变；更重要的是，部分与癌症相关的基因出现变异，暗示了它们可能因此免受辐射侵袭。
研究人员认为，这些突变基因似乎藏有可对抗癌症的秘密。事实上，过去就有研究显示，暴露在辐射中的植物会加速基因突变，部分物种甚至演化出新的化学物质，让自己免受辐射伤害并保护DNA。
科学家也指出，早期植物演化时，地球的自然辐射值远比现在高出许多，物种为了求生存，可能开启某种「休眠状态」。不过，大型动物身上是否也有相同的保护机制，仍有待进一步研究。
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