Dolly the sheep was the first cloned mammal, but scientists have struggled to reproduce even the early steps in people. Now a team in Oregon have used a skin sample and a woman's egg to produce some early cloned human embryo. _________________________ In theory this could be used to repair the damage after a heart attack or the brains of patients with Parkinson's disease. However, other experts say there are easier, cheaper and less controversial sources of stem cells. 多利羊是世界上第一只无性繁殖的哺乳动物,但科学家在人类(无性繁殖方面)至今仍处于早期阶段.现在俄勒冈州的一个团队用一个皮肤样本和一个卵细胞成功制 造出一些早期无性克隆的人类胚胎. _________________________ 理论上这个干细胞源能够用来修复心脏病发作(后的心脏)或者帕金森 症患者的大脑.然而,其他专家声称有更简单、更廉价,并且争议度更低的干细胞来源.
