Several teams of researchers around the world are believed to be working on ways of modifying the chromosomes of human egg cells with a view to moving towards “germ-line” gene therapy, as the process is called. Germ-line refers to the “germ” cells – sperm and eggs – that pass on genes to future generations.
However, other scientists have called for a moratorium on editing the human germ-line, arguing that it is ethically unacceptable because it is too unpredictable and too risky.
Nevertheless, researchers at Harvard Medical School in Cambridge, Massachusetts, have attempted to use the Crispr (pronounced “Crisper”) gene-editing technique on human ovarian tissue cultured in the lab to see if it might be possible to correct the defective BRAC1 gene involved in inherited breast and ovarian cancer. As ovarian cells develop into egg cells, the research is likely to have involved the altering of some immature egg cells, known as oocytes.
The work was carried out last year by Luhan Yang, a researcher working in the lab of the veteran Harvard geneticist George Church. But the study has not been published in a scientific journal and Dr Yang was unavailable for comment.
Professor Church emphasised that the work was purely experimental. He said that it was carried out on human ovarian cells cultured in a laboratory dish and there was no intention of fertilising any eggs or transplanting them into a woman. (Read more from “American Scientists Are Trying to Genetically Modify Human Eggs” HERE)