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This is Scientific American's 60-Second Science. I'm Cynthia Graber. This will just take a minute.

Thousands of medieval European books survive to this day. Authors and scribes carefully handwrote the works on parchments made of animal skins. But the writers didn’t always bother to sign and date their works. So we had no way of knowing where and when most of the documents are from. Until now.

Researchers at North Carolina State University have demonstrated that they can reliably extract DNA¹ samples from such parchments. Each manuscript offers up, they say, a wealth of genetic² information, because as many as a hundred animals contributed skins for one book.

The scientists propose recording³ DNA data from all books for which we do have a reliable date and place of origin. These reference samples would create a DNA library of dates and locations. Then the mystery manuscripts could be compared against that DNA database.

The North Carolina investigators⁴ are presenting the technique for dating old manuscripts at the upcoming annual meeting of the Bibliographical⁵ Society of America. And they’re still working on improved techniques to harvest DNA while doing minimal⁶ damage to the original priceless parchments. A way to further illuminate⁷ those illuminating⁸ books.

Thanks for the minute for Scientific American's 60-Second Science. I'm Cynthia Graber.

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1 DNA
(缩)deoxyribonucleic acid 脱氧核糖核酸
参考例句：
DNA is stored in the nucleus of a cell.脱氧核糖核酸储存于细胞的细胞核里。 Gene mutations are alterations in the DNA code.基因突变是指DNA密码的改变。

2 genetic
adj.遗传的，遗传学的
参考例句：
It's very difficult to treat genetic diseases.遗传性疾病治疗起来很困难。 Each daughter cell can receive a full complement of the genetic information.每个子细胞可以收到遗传信息的一个完全补偿物。

3 recording
n.录音，记录
参考例句：
How long will the recording of the song take?录下这首歌得花多少时间？ I want to play you a recording of the rehearsal.我想给你放一下彩排的录像。

4 investigators
n.调查者，审查者( investigator的名词复数 )
参考例句：
This memo could be the smoking gun that investigators have been looking for. 这份备忘录可能是调查人员一直在寻找的证据。 The team consisted of six investigators and two secretaries. 这个团队由六个调查人员和两个秘书组成。来自《简明英汉词典》

5 bibliographical
书籍解题的，著书目录的
参考例句：
Full bibliographical information should be enclosed after the main text. 文献资料另编录于论文本文之后。 See the bibliographical note under St Anne. 看到书目下的注圣安妮。

6 minimal
adj.尽可能少的，最小的
参考例句：
They referred to this kind of art as minimal art.他们把这种艺术叫微型艺术。 I stayed with friends, so my expenses were minimal.我住在朋友家，所以我的花费很小。

7 illuminate
vt.照亮，照明；用灯光装饰；说明，阐释
参考例句：
Dreams kindle a flame to illuminate our dark roads.梦想点燃火炬照亮我们黑暗的道路。 They use games and drawings to illuminate their subject.他们用游戏和图画来阐明他们的主题。

8 illuminating
a.富于启发性的，有助阐明的
参考例句：
We didn't find the examples he used particularly illuminating. 我们觉得他采用的那些例证启发性不是特别大。 I found his talk most illuminating. 我觉得他的话很有启发性。