Targeting Minority Embryos
by David Prentice
December 31, 2009
Two recent papers–one published online by the New England Journal of Medicine and one just published in Nature Methods–analyzed the genetic ethnic diversity of some of the existing human embryonic stem cell (hESC) lines. One group examined 47 hESC lines, while another checked 42 hESC lines; there were 9 lines that both groups checked, for a total of 80 different lines investigated, including some of the most-used hESC lines and some of the few newly-approved hESC lines.
Not surprisingly, they found that most of the hESC lines represent a limited genetic ethnic diversity, primarily from European and Middle Eastern, as well as some East Asian, descent. The University of Michigan group seems to think this is surprising, but in truth it is not surprising and has been noted for years.
Why is this lack of genetic diversity not surprising? Thus far, the embryos destroyed for hESC lines are all taken from in vitro fertilization (IVF) clinics. As many have pointed out for years regarding the hESC lines, the IVF technique is expensive, so the sample is self-selected for those who can afford the IVF practice. The sample is further restricted to those parents who are willing to sacrifice their so-called “leftover” embryos to science. They also found that more than one cell line came from the same embryo donors; again, common sense would have indicated that given the selection, this would be the case.
Perhaps the Michigan group was simply naive regarding their expectations of wider genetic ethnic diversity in the hESC lines. The source of the embryos is sometimes actually given in the published hESC papers, e.g., Thomson’s original 1998 paper noted “IVF clinics at the University of Wisconsin School of Medicine and at the Rambam Medical Center”; and four of the five original lines did indeed come from Israeli embryos. Continue reading »




