Although Genetic testing proves the Turkification of the region rather than Azeris being of Turkic stock, it also shows that the region is a mixed one. Though the population of Azerbaijan is culturally diverse, genetic testing has revealed common genetic markers that support an autochthonous background for most Azeris. A 2002 study found that: "Y-chromosome haplogroups indicate that Indo-European-speaking Armenians and Turkic-speaking Azerbaijanians from the republic are genetically more closely related to their geographic neighbors in the Caucasus than to their linguistic neighbors elsewhere."[5] The authors of this study suggest that this indicates a language replacement of indigenous Caucasian peoples. There is evidence of limited genetic admixture derived from Central Asians (specifically Haplogroup H12), notably the Turkmen, that is higher than that of their neighbors, the Georgians and Armenians.[5] MtDNA analysis indicates that the main relationship with Iranians is through a larger West Eurasian group that is secondary to that of the Caucasus, according to a study that did not include Azeris, but Georgians who have clustered with Azeris in other studies.[6] The conclusion from the testing shows that the Azeris are a mixed population with relationships, in order of greatest similarity, with the Caucasus, Iranians and Near Easterners, Europeans, and Turkmen. Other genetic analysis of mtDNA and Y-chromosomes indicates that Caucasian populations are genetically intermediate between Europeans and Near Easterners, but that they are more closely related to Near Easterners overall.
Many place names in the present day Republic of Azerbaijan and Iranian Azarbaijan have Persian roots. Tabriz, Baku, Absheron, Ganja, and the country (as well as people) name itself Azerbaijan, are just a few examples. Also, many of the cities in these regions were founded before Turkic tribes reached the area. The first mention of Baku was in 885, before the Turkic invasions of the 10th and 11th centuries.
Archaeological evidence discovered in these regions show a large Zoroastrian, a monotheistic Iranian religion, influence along with an Iranian presence of more than 3000 years, starting with the settlement of the Medes in the area, both of which shaped the Iranian identity of the region that lasted until the Turkic invasions.[33] However, no evidence has been discovered that the Huns ever created permanent settlements in the area, as some Turkish historians claim.[34]
Scholars see cultural similarities between modern Persians and Azeris as evidence of an ancient Iranian influence.[35]
Azeri's celebrate a number of Iranian holidays, most notably Norouz. Researchers also describe the lives of Azeri villagers and Persian villagers to be very similar in terms of tradition and culture. The literature of the region was also written in Persian, with writers such as Qatran Tabrizi, Shams Tabrizi, Nezami, and Khaghani, writing in Persian prior to and during the Oghuz invasions.
Also, remnants of former Iranian tribes that survived Turkification also provides evidence of the Iranian character of Azeri's. The Talyshs and Tats are both an Iranian people who speak Iranian languages, with Tats speaking a dialect of Persian.[36][37]