a his & hers weblog of worlds apart
A group at Stanford published an article on the ethics of using racial categories in human genetics last week. The terms race and ethnicity are often used interchangeably to describe both the cultural and genetic relationship between different groups. I will be the first to admit that I do not completely understand the complicated distinction between these terms. I will also admit that the topic of race, ethnicity and genetics makes me uneasy, given the historical underpinnings that this relationship holds.
In any case, “where are your ancestors from?” is a common question in clinical genetics, as we know that there are specific diseases that are more common in certain populations. Asking this question can be an important clue as to what to look for on the clinical and molecular level.
The Ashkenazi (Northern and Easter European) Jewish population provides an interesting example of the interaction between genetics and society. As a whole, we tend to know more about the genetics of diseases that affect the Jewish population, in comparison to other populations. There are a couple of reasons for this:
1. Jewish peoples (Ashkenazi, Sephardic and Middle Eastern) are historically distinguished by a specific religion, a distinct place of origin and a well-defined pattern of migration. As a result of genetic bottlenecks and subsequent genetic drift, the genes in the Jewish population are more uniform in comparison with more varied and less defined populations.
2. Traditionally, this population is interested and willing to participate in genetic carrier testing programs and research.
This second point is clearly illustrated by an innovative yet controversial Orthodox Jewish genetic screening program called “Dor Yeshorim,” which was established in the ’80’s by a Rabbi who lost four children to a genetic condition called Tay-Sachs disease. You can read more about the scientific details here, but essentially this program tests individuals to see if they silently “carry” common Jewish genetic mutations that could potentially result in genetic disease in their children, depending on who they choose to reproduce with.
An example of how Dor Yeshorim works:
A teenager has his blood drawn by Dor Yeshorim (DY) at school one day. A couple years later he meets a girl he likes who has also been tested through DY, and they start dating. When their relationship becomes serious (but before they fall in love, ideally) they call DY, give their unique identifying numbers, and are told whether or not they are “genetically compatible.” If they are not compatible, it is presumed that they each silently carry a genetic mutation for the same disease-and therefore their future children are at risk to inherit that disease. If they are genetically compatible, then it doesn’t necessarily mean that they free of genetic mutations, but that they don’t carry genetic mutations for the same disease, and therefore their future children are not at risk for those diseases.
DY is still an international presence in the Orthodox community today, and currently provides testing for approximately 10 diseases that disproportionately affect people of Ashkenazi Jewish descent. While genetic screening programs are now common for all populations (newborn screening, prenatal screening), I have always found it interesting that a population who, arguably, has one of the most complex historical relationships with “genetics,” was also one of the first to embrace it with open arms.