oa Ethnitest: A basic genetic tool in the assessment of ethnic origin for medical research and commercial utilization

The application of DNA-based methods for inferring ethnicity to investigate criminal cases has been well documented in recent literature. Based on self claimed ethnicity, numerous human diseases and the efficacy of therapeutic drugs have been linked to ethnic backgrounds. These racially-related diseases and drug responders included, but not limited to, cardiovascular disorders, sickle cell anemia, breast cancer, prostate cancer and responders to the therapeutic agent BiDil (hydralazine hydrochloride and isosorbide dinitrate) for treating congestive heart failures. Surprisingly, for all these cases no DNA based ethnicity method was used to verify the observed link between the ethnic origin and the risk for the specific medical ailment. The most probable cause is lack of a test that has the capacity to separate between the disease-causing genes and the markers for assessing ethnicity in genomic DNA. To this end, a logarithmic method was developed and validated utilizing the disease free STR genetic markers, which have demonstrated their suitability to separate between the two entities. The developed software system is currently used by our laboratory under the commercial name "Ethnitest" for inferring ethnic composition in racially admixture- individuals. The assay demonstrated low error rates and can accommodate more than ten population groups with distinct and proportional likelihood probabilities. Among self-claimed African American, Caucasian, Asian and Hispanic American populations, the assay demonstrated that 20%, 35%, 55% and 95% of these cases, respectively, are consistently admixtures. Upon further investigations, self-claimed Hispanic populations from three different geographical regions (North, Central and South America) showed that they are invariably all admixtures. As expected, the major constituents of these admixtures were found to be Native Americans and Europeans. In contrast, self-claimed Africans showed minimal admixtures among West African populations. However, East African populations showed different admixtures with African, Asian and Middle Eastern as the dominant ethnicities. As expected, the composition of the North Africans revealed that it was mostly dominated by European and Middle Eastern. Among staged prostate cancer DNA samples from self-claimed African American, the Ethnitest showed only 50% to perhaps have an origin in the African American population. The impact of these assessments on disease disparity and personalized medicine will be discussed. Furthermore, the limitations in the application of SNP and gender based ethnicity assays on disease disparity will also be discussed.