Presentation of Microbial Signals via Maternal Cells: An Evolutionary Advantage of Mammals

The evolutionary lineage leading to mammals began over 300 million years ago when mammal’s ancestors diverged from those of reptiles and birds (Lefèvre et al. 2010). As one of the main challenges of offspring survival was moisture loss, early mammals developed skin secretions to prevent dehydration. These secretions later evolved to milk (Oftedal 2012), whose early form was composed primarily of antimicrobial compounds but later evolved to a complex mixture of components that maximized offspring survival.