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一婴儿可遗传三人基因 新胚胎试验惹争议


http://en.youth.cn   2012-10-26 10:45:00

Three-parent embryos signal a new future

美国科学家近日首次成功培育出包含2名女子和1名男子遗传基因的胚胎

In a breakthrough, scientists have for the first time created embryos using human eggs that contain DNA from three parents, paving way to prevent 'designer' babies from inheriting rare genetic diseases.

 

Researchers from the Oregon Health and Science University in the US fertilized eggs containing DNA from two women to grow them into healthy embryos in a lab experiment . The technique, designed for women with mutations in tiny structures known as mitochondria, can result in a range of devastating conditions including muscular dystrophy, The Telegraph reported.

 

It involves taking chromosomes from the mother's egg, which carry 99.8% of her DNA, and placing them in a donor egg which has healthy mitochondria but has had its own chromosomes removed.

 

The eggs were fertilized by sperm and almost half developed into healthy embryos.

 

The resulting children inherited 99.8% of their DNA from their parents and a tiny fraction from the donor.

The DNA from the second woman amounts to less than 1% of the embryo's genes, and it isn't the sort that makes a child look like Mom or Dad.

The Oregon researchers reported that tests of their technique on rhesus monkeys had shown it could create healthy offspring, but added that there were fewer issues with the quality of embryos in humans.

In the current study, about half the manipulated eggs failed to fertilize properly , and consequently these gave abnormal embryos," professor Robin Lovell-Badge , of the MRC National Institute for Medical Research, said. The current study findings are published in the journal Nature.

   据澳大利亚《每日电讯报》10月25日报道,美国俄勒冈健康科技大学的科学家们近日首次成功培育出包含2名女子和1名男子遗传基因的胚胎,从生物学上说,这些胚胎拥有一个父亲和两个母亲。

  参与试验的科学家称,他们一共培育出大约12个拥有一父两母的人类早期胚胎。培育方法如下:将一个未受精的卵子的染色体取出,植入另一个已经事先取出染色体的卵子内。再将这个卵子人工授精,培育成胚胎。

  卵子中的染色体包含了母体99.8%的DNA,所以胚胎的DNA主要来自提供第一个卵子的母亲和提供精子的父亲,可以说他们才是这个胚胎真正意义上的父母。

  来自第二个母亲的去掉染色体的卵子只为胚胎提供了线粒体DNA,在胚胎的全部DNA中所占比例不到1%,而且不会影响孩子的外貌。

  俄勒冈健康科技大学的科学家们称,他们不会用这些一父两母的胚胎制造婴儿。

  每5000个孩子中大约有一个会因线粒体DNA问题患上遗传疾病,其症状表现包括中风、痴呆、失明、耳聋、肾衰竭以及心脏病等。所以如果这种替换卵子线粒体DNA的技术能够被投入实际应用,将在预防遗传疾病方面发挥重大作用。

  然而这种技术会引发激烈的伦理道德争论。许多人担心,它可能成为将来“人工设计婴儿”的开端。

 
source : 中国青年网综编     editor:: 马婷
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