科学家用三人的DNA创造胚胎

hy2007

Embryos created with DNA from 3 people

LONDON - British scientists have created human embryos containing DNA from two women and one man, a procedure that could potentially prevent conditions including epilepsy, diabetes and heart failure.

Though the preliminary research has raised concerns about the possibility of genetically modified babies, the scientists say that the embryos are still only primarily the product of one man and one woman.

\"We are not trying to alter genes, we're just trying to swap a small proportion of the bad ones for some good ones,\" said Patrick Chinnery, a professor of neurogenetics at Newcastle University involved in the research.

The process aims to avoid passing onto children bad mitochondria genes, which are contained outside the nucleus in a normal female egg. Mitochondria are a cell's energy source, but mistakes in their genetic code can result in serious diseases like epilepsy, strokes, and mental retardation.

In their research, Chinnery and colleagues used normal embryos created from one man and one woman that had defective mitochondria in the woman's egg. They then transplanted that embryo into an emptied egg donated from a second woman who had healthy mitochondria.

\"The proportion of genes in the mitochondria is infinitesimal,\" said Francoise Shenfield, a fertility expert with the European Society of Human Fertility and Reproduction. Shenfield is not connected to the Newcastle University Research.

Only trace amounts of a person's genes come from the mitochondria, and experts said it would be incorrect to say that the embryos have three parents.

\"Most of the genes that make you who you are are inside the nucleus,\" Chinnery said. \"We're not going anywhere near that.\"

So far, 10 such embryos have been created, though they have not been allowed to develop for more than five days. Chinnery hoped that after further experiments in the next few years the process might be available to parents undergoing in-vitro fertilization.

Similar research has been conducted in animals in Japan, and has already led to the birth of healthy mice who had their mitochondria genes corrected.

Shenfield said that further tests to assess the safety and efficacy of the process were necessary before it could be offered as a potential treatment.

http://news.yahoo.com/s/ap/20080205/ap_on_sc/embryo_research
伦敦-英国科学家首次创造了含有两名妇女和一名男子FDA的人类胚胎，这一操作手法未来有可能避免发生包括癫痫症，糖尿病和心脏衰竭等疾病。虽然这只是初步研究，但已引起人们有关是可否用于转基因婴儿的担心。不过，在科学家们眼里，胚胎只是男女精卵受精的产物。

英国纽卡斯尔大学参与研究的教授-- Newcastle大学神经遗传系的Patrick Chinnery教授说：\"我们不是想要改变基因，我们只是想在小范围内用好基因换取坏基因： 。

该研究的目的是为了在一个正常的女性卵子内避免不良的核外线粒体基因遗传到下一代。线粒体是细胞的能量来源，但线粒体基因和它们的遗传密码有错，可能会导致诸如癫痫，中风，精神发育迟滞等严重疾病，。

在他们的研究中， Chinnery和他的同事先用由一男和有线粒体缺陷的一女创造的正常胚胎。然后，他们把该胚胎转移到第二位健康线粒体正常的妇人的已被“清仓”的卵内。

巴黎欧洲社会人类生育和繁殖的生育专家Francoise Shenfield 教授，并未参与英国纽卡斯尔大学的研究项目，他对媒体解释说：与核内基因相比“线粒体内基因是无穷小量的”。他。 由于人的基因只有极微量的是来自线粒体，所以专家们称：如果说该胚胎有三个父母，那是不正确的。

\"大部分的基因确定每人究竟属性如何，这些主要还是由来自核里的基因成分控制为主，“Chinnery说。 \"但我们还不很了解核内外基因如何控制\" 。

到目前为止， 已有10个这种胚胎被创造了，虽然胚胎均未被允许发育五天以上。 Chinnery希望经过进一步试验，在未来数年的过程中，可能会提供给父母在试管中受精的新手段。

类似的研究工作也在动物实验中进行了，在日本已有报道，通过纠正线粒体基因缺陷产生出健康的老鼠，。

Shenfield说，仍有必要进一步测试，以评估这一过程的安全性和有效性，才有可能发展成作一个潜在的治疗手段。