Genetics of Sub-Saharan African Human Population: Implications for HIV/AIDS, Tuberculosis, and Malaria.

Gerald Mboowa

doi:10.1155/2014/108291

Abstract

Sub-Saharan Africa has continued leading in prevalence and incidence of major infectious disease killers such as HIV/AIDS, tuberculosis, and malaria. Epidemiological triad of infectious diseases includes susceptible host, pathogen, and environment. It is imperative that all aspects of vertices of the infectious disease triad are analysed to better understand why this is so. Studies done to address this intriguing reality though have mainly addressed pathogen and environmental components of the triad. Africa is the most genetically diverse region of the world as well as being the origin of modern humans. Malaria is relatively an ancient infection in this region as compared to TB and HIV/AIDS; from the evolutionary perspective, we would draw lessons that this ancestrally unique population now under three important infectious diseases both ancient and exotic will be skewed into increased genetic diversity; moreover, other evolutionary forces are also still at play. Host genetic diversity resulting from many years of malaria infection has been well documented in this population; we are yet to account for genetic diversity from the trio of these infections. Effect of host genetics on treatment outcome has been documented. Host genetics of sub-Saharan African population and its implication to infectious diseases are an important aspect that this review seeks to address.

Highlights

HIV/AIDS, TB, and malaria are three important killer diseases globally; these continue to devastate more of sub-Saharan African populations, with a total of 27 countries
Modern humans appeared in East Africa about 200,000 years ago, spread out from sub-Saharan Africa approximately 100,000 years ago, and subsequently colonized the rest of the world in a series of migratory events [71]. This implies that ethnic populations that remained in subSaharan Africa have been exposed to malaria for periods long enough to shape their genetic structures by plasmodium unlike those that left this region around that time
Infectious diseases continue to present a major threat for human populations and, shape genetic diversity of human populations

Summary

Introduction

HIV/AIDS, TB, and malaria are three important killer diseases globally; these continue to devastate more of sub-Saharan African populations, with a total of 27 countries. I am compelled to propose that modern humans who migrated away from sub-Saharan Africa encountered new environment and exotic pathogens in their new geographical niches Those exotic pathogens and other evolutionary forces, which they met in the different areas where they settled, would account for unique genetics. The indigenous pathogens in sub-Saharan Africa coevolved with their hosts creating unique genetic profiles in these human populations. I propose that a form of Newton’s third law of motion happens during an interaction between host and pathogen; action and reaction are equal and opposite This implies that the selective pressure exerted by these pathogens onto selected host genes in response to specific pathogen genes received similar pressure from the host driving hostpathogen diversity observed as unique genetic profiles in both host and pathogen accounting for coevolution. In the antibiotic/antiviral era, drugs are likely to act as selective pressure creating genetic diversity in pathogen genomes as well as hosts’

Human Host Genetic Diversity and Infectious Diseases

Tuberculosis

Malaria

Findings

Concluding Remarks