Japan's government approved a request by scientists to conduct stem-cell experiments to create an animal-human hybrid and allow it to be brought to term.
日本当局近日核准科学家展开培养人兽杂交胚胎的干细胞尝试，并许可其足月临蓐。
Japan's science ministry last week gave provisional approval to a proposal from researchers at the University of Tokyo to create animal embryos that contain human cells and transplant them into surrogate animals, Japan's?Asahi Shimbun?newspaper reported.
据日本《朝日新闻》报导，日本文部科学省上周为东京年夜学研究职员的一项研究议题发出姑且许可，该研究打算培育含有人类细胞的动物胚胎，并将其移植到代孕动物体内。
The study would create a human pancreas in rodents using human induced pluripotent stem (iPS) cells. According to UCLA's Broad Stem Cell Research Center, these are cells that have been reprogrammed back into an embryo-like state and can be used to create virtually any other type of cell.
这项研究将操纵人类引诱多能干细胞（iPS）在啮齿动物体内构成人类胰腺。据加州年夜学洛杉矶分校布罗德干细胞研究中间先容，这些细胞已被从头编程回到胚胎状况，可以用来缔造几近任何其他类型的细胞。
Final approval from the ministry is expected next month, according to the British scientific journal?Nature.
据英国科学杂志《天然》报导，日本文部科学省估计将于下月正式核准这一尝试。
According to?Asahi, researchers will take fertilized eggs from rodents that have been gene-edited to remove the ability to produce a pancreas themselves. To this, they will add human iPS cells to create hybrid animal-human embryos.
据《朝日新闻》报导，研究职员将从颠末基因编纂的啮齿动物身上提取受精卵，以往除本身发育胰腺的能力。在此根本上，他们将添加人类的iPS细胞来缔造人兽杂交胚胎。
These in turn would be implanted into a host animal, in this case a rat or mouse, and allowed to grow.
以后，这些胚胎将被植进宿自动物体内，在这项尝试中是一只老鼠，并得以发展。
According to researchers, the goal of the experiment is to create organs viable for transplant into humans.
据研究职员称，这项尝试的方针是缔造出可以移植到人体的器官。
"Finally, we are in a position to start serious studies in this field after 10 years of preparation," said Hiromitsu Nakauchi, a researcher at the Institute of Medical Science of the University of Tokyo, according to?Asahi.
据《朝日新闻》报导，东京年夜学医学研究所的研究员中内啓光说:“颠末10年的筹办，我们终究可以起头在这一范畴进行严厉的研究。”
"We don't expect to create human organs immediately, but this allows us to advance our research based upon the know-how we have gained up to this point."
“我们没有期看能当即制造人体器官，但这让我们可以或许基于今朝所把握的手艺推动研究。”
apan had previously banned such experiments.
日本此前曾制止此类尝试。
It reversed its decision in March of this year after consulting with experts.
本年3月，在咨询了专家后，日本当局改变了决议。
The government has said that experiments like these can take place as long as researchers take steps to prevent the birth of a creature that contains a mix of animal and human genetics.
日本当局曾暗示，只要研究职员采纳办法避免人兽杂交动物的降生，如许的尝试便可以进行。
Researchers will also monitor the animal-human hybrids once they are born for up to two years and will suspend the experiment if they detect that brains inside the growing animals contain more than 30% human cells,?Asahi?said.
《朝日新闻》称，在临蓐后，研究职员还将对人兽杂交动物进行长达两年的监测，若是他们发现这些发育中的动物年夜脑中含有跨越30%的人类细胞，将暂停这项尝试。
While other countries have experimented on creating human-animal embryos, Japan is now the first country to support experiments that will allow the animals with human cells to come to full term.
固然其他国度也展开过缔造人兽杂交胚胎的尝试，但日本今朝是首个撑持这项尝试，许可胚胎发育到足月临蓐的国度。
Scientists in the US have experimented with pig-human hybrid fetuses and allowed them to develop for three to four weeks before destroying them, as required by US ethics regulations.
按照美国伦理律例的要求，美国科学家对猪与人的杂交胚胎进行了尝试，并让它们发育三至周围，然后将其烧毁。
But according to Jun Wu, a biologist at the Salk Institute in La Jolla, California, only about 1 in 100,000 cells in the fetuses were human.
但据加州拉荷亚索尔克研究所的生物学家吴军（音译）说，胚胎中只有年夜约十万分之一的细胞是人类细胞。
In the UK, scientists at King's College London, Newcastle University, and Warwick University created dozens of hybrid embryos that were used to create embryonic stem cells that could potentially treat a wide range of illnesses.
在英国，伦敦国王学院、纽卡斯尔年夜学和华威年夜学的科学家们缔造了数十个杂交胚胎，用于制造胚胎干细胞，这些干细胞有可能医治多种疾病。
Concerns about the ethical implications of such research remain.
人们一向耽忧这类研究的伦理影响。
Some bioethicists are disturbed by the possibility that human cells implanted into animals may behave unexpectedly, and could affect an animal's brain or cognition.
一些生物伦理学家担忧，植进动物体内的人类细胞可能会呈现料想以外的反映，并可能影响动物的年夜脑或认知。
"It is problematic, both ethically and from a safety aspect, to place human iPS cells, which are still capable of transforming into all types of cells, into the fertilized eggs of rats and mice," said Jiro Nudeshima, a researcher specializing in the ethical implications of life science research, according to?Asahi.
《朝日新闻》报导称，生命科学研究伦理题目研究员Jiro Nudeshima说：“将依然可以或许转换成所有类型细胞的人类iPS细胞植进老鼠的受精卵，这在伦理和平安方面都有题目。”
Nakauchi, the researcher proposing the experiment, dismissed concerns, saying that his experiments are focused on the creation of specific organs, and not the development of a new species.
提出这一尝试的研究员中内啓光辩驳了人们的耽忧，称他的尝试存眷的是特定器官的缔造，而不是新物种的培育。
"We are trying to do targeted organ generation, so the cells go only to the pancreas," he said, according to?Nature.
据《天然》杂志报导，他说:“我们正在测验考试培养特定的器官，如许细胞就只能达到胰腺。”
He added that in his previous experiments, the number of human cells inside of a sheep embryo has been extremely small.
他弥补说，在他之前的尝试中，绵羊胚胎中的人类细胞数目很是少。
"The number of human cells grown in the bodies of sheep is extremely small, like one in thousands or one in tens of thousands," he said, according to?Asahi.
据《朝日新闻》报导，他说:“绵羊体内发展的人体细胞数目很是少，只稀有千分之一或数万分之一。”
"At that level, an animal with a human face will never be born," Nakauchi said.
他说：“在这个程度上，是不会生出长着人脸的动物的。”