Map of the "Hellenic Race".

This map shows the genetic similarity of modern populations to the Greeks.

As it is clear in the map, Greece, southern Italy, the Balkans, and western Turkey are the regions most closely related to the Greeks.
This should not come as a surprise, since it is thought that Greek, as a language, was closely related to ancient Illyrian (which was spoken in the region of Dalmatia, western Balkans), Thracian (spoken in the region of Thrace, south-eastern Balkans), as well as Phrygian and the Anatolian languages (spoken in western Anatolia). The Illyrians were thought by some ancient Greeks to also be Greek, or at least less-Barbaric compared to other peoples, so it would make sense if they were genetically related. It is also very likely that the genetic similarity between western Anatolians and Greeks has existed even before Greek colonization to the east. Even if that is not true, the western part of Anatolia was an important center of Hellenism in the middle ages and really up until the early 20th century, and many Greeks from the mainland migrated there. Those who converted to Islam during Ottoman rule and assimilated to the Turkish population are responsible for the genetic similarity between western Turks and Greeks. The opposite hardly happened, because it was illegal under Sharia law for Muslims to convert to Islam, and it would be foolish to do so, since Christians had fewer rights in the Ottoman empire.

One might wonder "How come the southern Slavs are related to the Greeks? Did they not come centuries later?". While it is true that Slavs migrated south around the 7th century A.D, it should be noted that Slavs are just a linguistic group and that they are not racially homogenous. Most modern southern Slavs are descendants of slavicisated native Balkan populations, like the Pelasgians, who were genetically related to the Greeks.

In the case of southern Italy, things are very simple. The region is also known as "Great Greece" because many Greeks migrated there. These populations remained Greek-speaking and Hellenic even up until the 11th century AD, when they were de-Hellenized and linguistically Latinized. This is one of the reasons why modern Greek and Italian cultures are considered to be identical. What is odd, however, is that northern Italy is also genetically similar to Greece, which is actually surprising considering they were never Hellenic, never had Greek colonies and the fact that the region was subject to many migrations from Germanic and Celtic tribes. This could possibly suggest that the original people of the region (the original Romans, Etruscans, etc) were actually Hellenic or Hellenic-like. Also surprising is the fact that Ireland and Scotland are not very genetically related to Greece, even though they are anthropologically classified as Mediterranean. This could be explained by the fact that they are from Iberia, therefore west Med, not east Med.

Another conclusion we can draw from this map is that Greeks are more related to European populations than to the Middle East

~Michael C. Dim.