Afro-European Genetic Admixture in the United States June 2004
Association of African Genetic Admixture with Resting Metabolic Rate and Obesity Among Women
This is a novel approach to finding genes that underlie ethnic variation in disease risk, based on studying populations of mixed descent. Admixture mapping is based on the same principles as linkage analysis of an experimental cross between inbred strains. Using panels of markers that are chosen to be highly informative for ancestry, it is possible in principle to extend this approach to admixed human populations where the history of admixture is not under experimental control and the ancestral populations are not inbred strains . Our work in this area is an extension of earlier work on the epidemiology of ethnic variation in risk of cardiovascular disease and diabetes.
Genetic Identity Ancestry Testing
With the human genome finally sequenced and recent advances is DNA technology using Single Nucleotide Polymorphisms (SNP) a new type of genetic test called BioGeographical Ancestry (BGA) can be generated by analyzing your DNA. In the human populations, there are some individuals of relatively pure BioGeographical Ancestry (BGA), such as sub-Saharan Africans from Nigeria, Europeans from Northern Europe, East Asians from Northern China and Native Americans from isolated regions of Southern Mexico. In other places, such as the United States, there are recently (in evolutionary time) admixed (admixture is the blending of two or more races within individuals) peoples such as African Americans (a blend of African and European BGA) and Hispanics (a blend of Native American and European BGA). Of course there are more than just four continental population groups, and a large fraction of the world population is admixed to a greater or lesser degree. SNP technology can determine your precise ancestral proportions. For example, it might reveal that you are of 80% African and 20% Indo-European, or 95% African and 5% Indo-European ancestry (or some other mix/ratio, as the case may be).
The human DNA code (genome) contains 3.1647 billion chemical nucleotide bases (A, C, T, and G). Approximately, 99.9% of these nucleotide sequences are the same in all people. This leaves about two million nucleotides (0.1%) that are unique from person to person. These sequence differences account, in part, for why we look, think, and behave differently and some of these nucleotide variations (about 2,000 or so) are dramatically different amount the various races. It so happens that by analyzing your DNA sequences using Single Nucleotide Polymorphisms (SNP) technology at some of these latter sites, it is possible to not only infer your major ancestry (which you probably already know) but your ancestral proportions (which, you probably do not know). For example, have you ever wondered whether you are of purely Indo-European origin or a blend of Indo-European and Native American (or other) ancestry? If you are of majority African heritage, have you ever wondered whether you are also of Indo-European descent, or perhaps of East Asian descent? If you know that you are a blend of ancestries, do you know what proportions you are of each? SNP technology has allowed us to precisely determine your ancestral admixture.
Single Nucleotide Polymorphisms (SNPs) can be use to determine your Biological ancestry proportion by identifying Ancestry Informative Markers (AIMs) within your DNA. AIMs are located in that 0.1% of the human genome that differ in sequence between the world’s various populations and by identifying AIMs it is possible to make a strong inference of your ancestral mix. The Pennsylvania State University (PSU) has identified the world’s only comprehensive set of AIMs. This patent pending science was published in late 1999, and then again in 2001 and 2002 (See Parra et al.; Pfaff et al.; and Frudakis et al). SNPs enable the determination of individual ancestry proportions (called “admixture ratios‿) from DNA. Because it uses genetic markers spread throughout all the chromosomes, with unique and specific anthropological characteristics, it is quite a distinct product from STR, Y-chromosome or mitochondrial DNA testing used in other types of anthropological settings.
For more information:
Minority Health & Health Disparities Research Center