Gene's Battle with Microbes Promotes Evolutionary Innovation in Humans
The lactoferrin gene arose in early mammals approximately 160 million years ago, and can still be found in the genomes of humans and other primates. New research shows that lactoferrin, whose original function was to transport nutrient metals such as iron, has undergone “rapid” evolution to develop another role – immune defense against microbes that cause potentially deadly diseases of meningitis, pneumonia and sepsis.
University of Utah researchers believe changes in the lactoferrin gene show evidence of an ongoing battle that drives evolutionary innovation as microbes find new ways of infecting humans and lactoferrin evolves to repel the invaders. The study shows that natural selection has acted on lactoferrin over millions of years, suggesting that lactoferrin has played an important role in the evolutionary success of living primates. In fact, differences in the lactoferrin gene still exist in different human populations across the world today.
The research also demonstrates how the emergence of a new immune function in a gene, such as the one in lactoferrin, can drastically alter evolutionary conflicts with microbes.