The article link below describes how a single species of gut bacteria can reverse autism-related social behavior in mice.
The fact that a single organism can have so much influence on mouse behavior and experience is also a glimpse not only into the powerful biological drivers that result in what all organisms experience as life, but indeed what life experience is founded on. Our behaviors and experience, including whether and how much we are social, as well as whether or not we remain a coherent part of the biological economy over time and so on are based on the relational climate that forms as a result of a parliament of organisms and environmental conditions which together operate as a coherent body which influence behaviors and experience on multiple scales.
The notion that we are an individual species, defined by our local genetics and completely separate entities from other species is dissolving as a useful means to clearly define biology. A lens that sees biology as a relational economy that transcends our notions of individual species – one that renders the image that a coherent biological body consisting of organisms of many different genetic makeups networked together in diverse ways, forming a meta body, complete with a coherent integrated metabolism and the defense mechanisms to defend that integrity in the face of antagonists – is a more appropriate lens.
https://www.sciencedaily.com/releases/2016/06/160616140723.htm
The Wisdom Of Life 