Hair, Feathers and Scales: How much do they have in common?

How much do they have in common?

At first glance, it would seem like birds, mammals and reptiles are about as different as could be.

That’s of course until you speak with Dr Milinkovitch and his group in Switzerland about their landmark study in 2016. 
His data, which comes from studying specific reptile species points to the possibility that feathers and hair are in fact more closely related than ever imagined. Birds and mammals (including humans) are thought to share a common ancestor some 320 million years ago!

Scales in reptiles, feathers in birds and hair in mammals appear more closely related than once imagined.
 

Reference

Nicolas Di-Poï and Michel C. Milinkovitch. The anatomical placode in reptile scale morphogenesis indicates shared ancestry among skin appendages in amniotes. Science Advances  24 Jun 2016:Vol. 2, no. 6.