I'm currently reading chapter 540...and here they say that Gu Xiangwen and Gu Nianzhi aren't biologically related...however, I seem to remember that GXW's sister's(Gu Tian) daughter's DNA had a match with GNZ...Did I recall incorrectly or is it an error or is the mystery gonna further unravel?! ¯ (°_o)/¯