Complex sentence: Of these two, the only branch that has been confirmed in a native population outside of Ethiopia is E-M35, which in turn has two known branches, E-V68, E-Z827 which contain by far the majority of all modern E-M215 men.
Split into simpler sentences: Of these two, the only branch that has been confirmed in a native population outside of Ethiopia is E-M35, which in turn has two known branches, E-V68, E-Z827. E-V68 and E-Z827 contain by far the majority of all modern E-M215 men.