This reminds me of people in Soviet Union who chose to write “Russian” as their ethnicity in passport despite different ancestry (yes, there was such section in Soviet and later Russian passports until 1990s). Indigenous people of Siberia or Caucasus, Germans and Jews too familiar of ethnic prejudices were redefining their identity to open career opportunities. You could take either ethnicity of your father or your mother, being Russian was often considered the safest bet.