+------------SUBJ:V-N------------+                              
      +----COMP:N-N(of)---+            |         +------APPOS-----+   
      |           +MOD_ATT+            +COMP:V-N(+        +MOD_ATT+   
      |           |       |            |         |        |       |   
 Expression of __SP__ __NODE__ gene occurs in __SP__ ( __SP__ ) skin .
COMP:N-N(of) (expression,__NODE__)
MOD_ATT:N-ADJ (__NODE__,__SP__)
SUBJ:V-N (occur,expression)
COMP:V-N(in) (occur,__SP__)
APPOS (__SP__,skin)
MOD_ATT:N-ADJ (skin,__SP__)