BURGLARS HAVE been steadily running out of things they can safely leave behind at a crime scene. First came footprints, then fingerprints and stray(零星的，散落的) fibres. Even microscopic(微小的，需用显微镜看的) strands of DNA left on tools and surfaces have been used to catch the incautious(不小心的，粗心的). Now they have something else to worry about: fragments of genetic material in the air.
窃贼在犯罪现场能安全留下的东西正越来越少。先是脚印，然后是指纹和散落的纤维。就连留在工具和表面上的微量DNA链，也被用来抓获那些粗心大意的窃贼。如今他们又多了一件需要担心的事：空气中的遗传物质碎片。
All people, criminals and non-criminals alike, shed(脱落，散发) tiny traces of themselves wherever they go. Some of this material—mainly skin cells, dandruff(头皮屑) and saliva—ends up suspended as a personal debris(碎片，残骸) cloud that can hang around(停留，徘徊) after the person is gone. A new study published in Forensic Science International: Genetics, a journal, shows that volunteers who pretended to ransack(洗劫，翻箱倒柜地搜) houses in controlled tests could be identified from DNA pulled from the air 30 minutes after they scarper(逃跑，溜走)ed. As with most forensic(法医的，法证的) evidence, it alone is not proof of wrongdoing(不法行为，坏事). But it could raise some awkward questions for someone without a good reason to be there.
所有人，无论罪犯还是普通人，走到哪里都会留下自己的微小痕迹。其中一些物质——主要是皮肤细胞、头皮屑和唾液——最终悬浮成一片个人碎屑云，在人离开后仍能停留一段时间。发表在期刊《法医科学国际：遗传学》上的一项新研究表明，在受控测试中假装洗劫房屋的志愿者，在他们逃离30分钟后，仍可从空气中提取的DNA识别出来。与大多数法医证据一样，单凭它并不能证明有罪。但对于没有正当理由出现在那里的人来说，它可能会引出一些尴尬的问题。
Carried out by a team led by Chiara Fantinato at Oslo University Hospital, the study is an impressive application of methods to capture and analyse what is known as environmental DNA (eDNA)—the genetic traces left by an organism in its surroundings.(这项研究由奥斯陆大学医院的基娅拉·凡蒂纳托领导的团队开展，是捕获和分析所谓环境DNA（eDNA）——生物体在其周围环境中留下的遗传痕迹——的方法的一次令人瞩目的应用。) For more than two decades ecologists have used eDNA from water, soil and atmosphere to detect creatures without needing to see or capture them. The technique has been used to track elusive(难以捉摸的，难以找到的) Burmese pythons in the Florida Everglades(佛罗里达大沼泽地的缅甸蟒入侵问题) and to audit(审计，盘点) the inhabitants of Loch Ness. (Fish and plenty of eels. No plesiosaurs.)
这项研究由奥斯陆大学医院的基娅拉·凡蒂纳托领导的团队开展，是捕获和分析所谓环境DNA（eDNA）——生物体在其周围环境中留下的遗传痕迹——的方法的一次令人瞩目的应用。二十多年来，生态学家一直利用来自水、土壤和大气中的eDNA来检测生物，而无需看到或捕获它们。该技术已被用于追踪佛罗里达大沼泽地中难以捉摸的缅甸蟒，以及盘点尼斯湖中的居民。（有鱼和大量鳗鱼。没有蛇颈龙。）