We just published a paper in Genome Biology and Evolution – “Atopic Dermatitis Susceptibility Variants In Filaggrin Hitchhike Hornerin Selective Sweep“. It describes the unusual history of the genetic variation affecting the skin structural protein fillagrin. It turns out that a loss of selective pressure, adaptive restrains on a neighboring gene and a high mutation rate due to subexonic copy number variation shape the genetic variation in this locus. It also happens to be a major susceptibility locus for eczema.
It is a fitting, if minor example, for Haldane’s words almost a hundred years ago: “Now my own suspicion is that the Universe is not only queerer than we suppose, but queerer than we can suppose.” (Possible Worlds – 1927).
Also some nice commentary, ideas by @RazibKhan –Eczema as an Outcome of an Ancient Sweep
and
by EvMed Review – A hitchhikers guide to eczema