GRE Reading Comprehension: JiJing 352-GRE阅读机经352篇 - 165P6RYI4ALYJOWYK

Biologists studying wild monkeys sometimes need the genetic material DNA from a particular monkey to determine the animal's parentage. Until recently, DNA could be extracted only from blood. Collecting a blood sample required tranquilizing the donor animal. Now DNA can be extracted from hair. Monkeys shed large quantities of hair in places where they sleep. Therefore, researchers will now be able to determine the parentage of individual monkeys from DNA without tranquilizing the monkeys.