John Byrne was born on December 8, 1879 in Altclogh Town, Carrick Parish, Glencolumbkille Civil Parish, County Donegal. He was the oldest of seven children. His parents were William Byrne (born abt. 1845 in Altclogh, married February 16, 1879, and died January 7, 1895 at age 50) and Nabla Fisher (born abt. 1853 in Meenacharvey, County Donegal and died in Altclogh on July 7, 1918 at the age of 65).
I am not aware if William Byrne had any siblings.
Nabla Fisher was born to Edward Fisher, probably from Altclogh, and (possibly) Mabel Ward. Nabla had several siblings. Only two are known (Francis "Frank" Fisher born 1845, immigrated to the US in 1863 at age 18, married Bridget Carr in 1877, and died in Indiana in 1897) and (Patrick Fisher born in 1841, and married Bridget "Biddy" Doherty in 1868. Unsure of date of death.) I am unsure of other sibling names.