Ongoing Evolution

The immune system is constantly trained and reshaped by biological, ecological, and social factors. This chapter focuses on the human immune system and explores how admixture between early humans and Neanderthals could have reshaped their immune responses. It examines how different infectious diseases have influenced CCR5‐Δ32 allele distribution in human populations. The chapter explores how over‐reactive or abnormal immune responses observed today could be the legacy of past infectious diseases. It then proposes how the study of ancient human remains helps researchers to reconstruct changes in skeletal inflammatory phenotypes in past populations and explores the ongoing evolution of human immune system. The CCR5 protein is used by the human immunodeficiency virus (HIV) to gain access into immune cells (T‐lymphocytes), but the CCR5‐Δ32 variant offers resistance to HIV.