Dr Charles N. Rotimi

Title: Genetic diversity and health: Opportunities and challenges presented by African genomes

Africa is the common birthplace of all human populations. As a result, modern humans have lived longer on the Africa continent than in any other geographical regions of the world. This long evolutionary history has led to several important cultural and genetic characteristics of the African people. For example, greater genetic variation is seen in present-day Africa populations, resulting in more haplotypes, lower levels of linkage disequilibrium (LD), more divergent patterns of LD and more complex patterns of population substructure. Africa has the highest linguistic diversity in the world with an estimated 2,000 languages; notably, Nigeria as a nation has over 500 listed languages. Also, due to vast cultural practices and uneven economic developments, African populations display considerable phenotypic variation. Given these important observations and the critical role of Africa in human evolutionary history, it is surprising that there has not been a global effort to systematically sample African populations for a comprehensive documentation of the scope and extent of genetic variation on the continent. In fact, an argument can be made that Africa has been, for most part, left out of the genomic revolution to date. A stark demonstration of this point is the fact that, despite the well documented success stories of genome-wide association studies (GWAS) in identifying susceptibility variants for several human diseases (www.genome.gov/gwastudies), it is remarkable that only one GWAS, the MalariaGen Project, has been published in a large collection of African individuals to date. This observation is particularly troubling given that Africa is faced with the heaviest global burden of disease, the least equipped health care system and perhaps, the least technologically developed to take advantage of the growing health and economic success stories of the genomic revolution.

The inclusion of three African populations in the international HapMap and several more African populations in the 1000 genome project and the recent whole genome sequencing of a Yoruba and Southern African individuals are beginning to address this inequity in genomic research. This presentation will explore our current understanding of the scope of genetic diversity in Africa and its implication for health and human history. A case will be made that, by not fully engaging African populations in genomic research, scientists are likely to compromise the novel insights that could be gleaned from studying the different genetic architecture of Africa people. For example, reduced LD in African populations is likely to provide a better chance of identifying causal variants for human diseases and the long evolutionary history of the African people is also likely to advance our understanding of human adaptive history.