A recent letter to the New England Journal of Medicine has investigated the genetic ancestry of the most commonly used and widely distributed embryonic stem cell (ES cell) lines currently used in research, and highlighted the dearth of lines that originate from non-European populations. Dr Sean J Morrison, the author of the letter, with his Michigan University and international colleagues, described how this reduced genetic diversity might be problematic for the development of cellular therapies, which is the eventual aim of human ES cell research. Their letter states that potential benefit to patients may depend partially on the diversity of the ES cell lines available for research and clinical use.
However, what their research showed was that this potentially valuable diversity is being restricted by two issues. For several sets of cell lines, the use of embryos from common gamete donors was identified (which outside of a Petri dish would be like doing research only on a single set of siblings or half siblings and then trying to apply the findings to the general population). But the wider issue was that nearly all stem cell lines currently in use are of European and Middle Eastern (most likely Israeli) origin, with the exception of just two lines that would have been derived from donors who were of East Asian ancestry.
The scientists raised concerns that all widely distributed stem cell lines lacked population diversity. Most significantly, there are no cell lines that derive from populations with recent African ancestry. Their report recommends that future efforts to create new stem cell lines for distribution should now emphasise under-represented populations. By increasing the genetic diversity of human ES cell lines available for research, scientists will be better placed to assess to what extent the ancestry of stem cell lines influences disease, whether cellular therapies being developed will be effective in people who are not of European origin, and will reduce the risk that the potential benefits of stem cell research will be limited only to patients with certain ancestries.