Who was Jack London's biological father from the biography, Jack London?

Author, Daniel Dyer, claims that William Chaney and Flora (London's mother) were actually married; other accounts have them as common-law spouses, or even as transitory lovers. The author agrees with Jack London himself and other biographers that despite his denials, Chaney was London's biological father, and according to Dyer, when contacted by London, Chaney denied all and cut off his son from communication.