Stem-cell method preserves embryo @ Boston Globe

Stem-cell method preserves embryo Mass. lab hopes to end standoff By Gareth Cook, Globe Staff

The technique builds on a fertility clinic procedure known as ``preimplantation genetic diagnosis." With PGD, after technicians fertilize an egg in a laboratory dish, they allow it to grow into an embryo of approximately eight cells. They then remove one cell and test it for signs that the embryo carries chromosomal abnormalities or genes for diseases such as cystic fibrosis. The results guide decisions about which embryos to implant in a woman. The precise risk PGD poses to embryos is not known but is thought to be relatively small, and many healthy children have been born from embryos from which a cell was removed.

To create stem cells, the ACT team proposes working in the future with couples already having PGD performed. The key difference is that after the cell is removed, it would not be immediately tested, Lanza said. Instead, it would be allowed to grow in a laboratory dish overnight, in the hope that it would divide, creating two cells. One of the cells would be used for the genetic testing and the other to create a batch of embryonic stem cells, using a recipe the scientists described in the Nature paper.

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