Coding Fregoli's illusion

I Smell a Rat!

“…I've been privileged to write these Evolutionary Anthropology commentaries for many years, and there aren't always brand‐new subjects to discuss. In fact, a decade ago I wrote about the genetic basis of the olfactory system with which we detect smells, describing the remarkable expression pattern of these genes. Most of that story is still basically current, in spite of some tentative new clues about the mechanisms …”

“…That would mean there's no need for a specific adaptive explanation for species‐specific gene counts. However, such a high level of proliferation isn't true of most gene families, though it is seen in other kinds of open‐ended detection systems, such as the immune‐defense system in animals and similar systems even in plants and microbes . That similarity reinforces the idea that the olfactory system evolved its complexity in a selection‐based way to combat diverse unpredictable threats.…”