Modern inhabitants of Turkey are more or less similar genetically to greeks, it's because they are mostly accultured. Both sides like to think the populations transferred to each country through succesive migrant and refugee waves, but genetics doesn't show that. The people who belonged to the Byzantine empire didn't magically evaporate after conquest, nor did they all mantain their greek culture. The same way that the vast majority of the population in Algeria is genetically "kabyle", but self-identify as culturally arab. Or the way the name of the country France is culturally derived from a germanic tribe, even though they accounted for a very small percentage of the population that was mostly gallic or gallo-italic.
That's why I think turks and greeks hating on each other is ironic, they're linked not only by culture and history but also by blood.