Regulus
It is very good question but the answer is not easy.
I must say that I read some of the assumptions that the R1a in the Balkans is very old but Klyosov's assumption about 11,650 ± 1550 years BP, is really exceeded all expectations.
What can one say about such bold statements?
Variant a) If the Klyosov is right it is possible that the R1a in the Peloponnese is very very old
Variant b) If we stick to the official history (which has no anchor points in genetic research) R1a may be much more recent,
Variant c) It is possible that the R1a older than the official historiography, but not as old as it claims Klyosov
Variant d) It is possible that part of R1a is very old and the other part is the newer variant
Variant e) it is more a question than an answer, how is it that the Slavs and Avars present only Slavic R1a, and what about the Avar haplogroups?
And so on. Certainly in-depth research, including determination of the age specific population (the time when the population appeared in any territory) are demanding and expensive, researches must find human remains from different periods that can be used to test DNA sample.
However, How and no and I can have the difference in assumptions, which does not mean that one can reliably say who is right, and it is good that there are different views, because only through mutual discussion, we can get closer to the truth.
Own thesis:
Originally, Slavs are R1a people
Originally, Serbs are I people
Serbian people, in genetic terms, are not Slavs
Serbs used I language, completely different from R1a Slavic language
One of the keys to the secrets is discover of ancient I language
How have linked the two very different populations I people and R1a people, and why I people received language and culture of R1a people not known
General confusion, there were in the Balkans and I and R1a populations both of which are old and need to determine how old, also from other parts and I populations and R1a populations came and these populations ranged from the Balkans to Central Europe, Ukraine, Black Sea, Karpata and back to the Balkans
Vinca culture belonged to either I or R1a population
In ancient times and earlier I and R1a tribes probably were classified as some of the Thracian, Celtic, and Illyrian tribes
History of the Balkans will be re-written when it comes to relevant data about population I and R1a
But I and R1a people are completely different, I people probably come from Anatolia and R1a people probably come from Central Asia.
Maybe I have a clue who were I peoples - Sarmatians . Pliny Elder mention Sarmatian tribes of Serboi ( Serbs) and Heruvatoi ( Croats ) ..Diodorus Siculus say that Scytians moved parts of Medians to they kingdom during they rule in Asia in VII century BC , and that Medians are called Sarmatians which means Solar Medes .And Kurds are descendants of Medians , thats why Sarmatians and Kurds both have I2a2 .I2a2 is not a Slavic haplogroup , it is Saramatian . Slavs are mainly R1a and they are descendants of Scytians and nations they have conquered - Melanhleni , Neuri ,Androphage, ... I2a2 is strong in all regions where Sarmatians use to live : Ukraine ( coast of Black see -homeland of Sarmatians after they conquered Scytians , also there was some movement of Serbs in XVIII century to east Ukraine , and there is report by Byzantine patriarch Nichophorus that parts of Serbs and Croats have escaped on empty lands in today Poland and Slovakia-Bielochorbatoi around Krakow and Lendzans "those who live on empty land" -Serbian word ledina means the same ,and its cognate to Germanic word land , in today Ukraine and Belarus - Boiki and Rusini by Rascia one of Serbian states in Midle ages . It is interesting that higher level of I mth haplogroup in Europe is in Boiki 10% , and that haplogroup use to be 10% in Scandinavia during Midle ages but it has decreased. Boiki do not call themselves that, its an egzonime , because they use word bo same to Bosnian bona or bo/bolan that is used in Mačva in Serbia ), Moldavia and Romania ( also homeland of Sarmatians after they conquered Scytians , after colapse of Huns hier lives Ants whose names are Iranian- Sarmatian , also during the Hunic empire Saramatians use to live in Banat) , Sardinia ( Vandals mixed with Alans after move to Africa setled hier ,I think there is some I2 in Lybia to . Tacitus say that Vandals were Saramatian nation) ,Serbia - Croatia -Bosnia -Macedonia-Montenegro (setled by Sarmatian tribes of Serbs-Serboi-Siraci and Croats -Harauati mentioned by Pliny the Elder like Sarmatian tribes), Bulgaria ( Bulgarians could partialy been Sarmatian , and there is emperor Constantine setling of 500.000 Sarmatians in Thrace , same is the case in Greece , also around Thesaloniki was first setling place of Serbs , Albania was part of Car Dušans empire , north Albania to river Liesus was in Serbian state Dioclitia-Duklja and some sources say Serbs and Croats use to hold to Apolonia - today city of Fier) , Hungary ( Magyars brought with them parts of Yazigs , in Hunic and Avar empire Sarmatians lived in Banat , and Turks chase population of Banat diper in to Hungary, there was also Serb and Croatian setling in Hungary), Slovenia( there used to live Venets probably cousins of Vandals , also great numbers of Croats escaped there infront of Turks ),north parts of Ossetians ( others are quite simillar to surounding nations - probably has something to do with custom to rape whole conquered village,haplogroup G is conected to goath breaders and is present on every big mountin like Caucasus , also high in Alpes-Austria, Apenins-Italy , Asia Minor ) , Czech republic ( Croats move on Balkans from there , in X century there was a Croatian kingdom under Slavnik family, Serbians comed from Boiki- Bohemia caled after Celtic tribe Boii, in Bohemia there is 3-4 times higher procent of I2a2 then in rest of Czech- 14,6% in Klatovy and 9,2% in Pisek , rest about 4% ) , Mordvinia republic in Russia ( in the area around Ryazansk moved groups of Roxolani , today Volga Tatars in this republic has 18,4% I2a2) ,Spain ( Alan and Vandal setlement , Katalonia), France ( few Alanic kingdoms) , England ( 5000 Sarmatian auxiliars - king Arthur) , Germany(Bavaria is also caled after Boii and could be part of Boiki , in southern Germany there is 5% I2a , and in the rest 1-2% ). So all of I2a2 can be explained by Sarmatians moving , and its not Slavic , it is spread in Slavic countries because they use to live on same lands and mixed a lot. When King of Germany Heinrich conquered White Serbs he bild fortres of Meissen in place of their main city Gaza , so center of White Serbs was not in todays Lužica but further west , so Sorabs are mainly descedants of Lugii , Celtic tribe , they have 60% of R1a . That could be partialy because Czechs rulers kill a lot of them during wars in Xth century , and there was probably a lot of raping .
There is also theory that I2a2 is paleolitic haplogroup who setled Balkans during last glacial maximum , that makes no sence because Greeks and Albanians -old popultions have less I2a2 then Serbs and Croats-newcomers , also Mesapi population of southern Italy has no I2a2 and they are Illyrians that crossed Adriatic see.They even use to speak simillar languague to Illyrian.
There is few teories how Serbians and Croats accepted Slavic languague , one that sound most reliable to me is that Sarmatians use to marry Slavic speacking womans while they use to rule over the mases of Slavs around Pripyat - like all Iranians they use to have more then one woman . Since Sarmatians and they womans of Sarmatian origin use to spend most of the time in wars and horsebriding , Slavic wifes look after the childs , so childs have lurned Slavic languague from them .
Eneti were from Paphlagonia and there is also higher percent of I2a2 , displaced a bit to the west due to Turks conquering , they settled in today Veneto there , in neighbouring Trevizo(9%) and Slovenia(22%) is higher I2a2 than in the rest of Italy.Same roots as Eneti has Vandals , Anti , Veneti , Wends,... In northeast China - Xiangyang use to live nation Yuezhi who were caucasian , they have same roots like Alan tribe of Asii , and Yazigi .It is interesting that German gods are separated in two groups Vaeniri and Aesiri , maybe the names had to do someting with worshiping of particular group of gods .
Kurds have K haplogroup ,and the Serbs to around 3% in some aerias up to 7% . Also Volga Tatari - inhabitants of Mordvinia republic in Russia where setled some Roxolans has 7,99% K and 18,4% I2a2 . Think that is K*.Also there is K* haplogroup in north Ossetia from 0% in Digora up to 21,7% in Zamankul.
I would like to say that I am not claiming that Serbs do not have Slavic origins at all , I only say that they ancestor were Sarmatians , who use to mix a lot with Slavs , so Serbian mthDNA is much closer to Slavic than yDNA , so Serbians ( and Croatians ) are Slavs but mostly by mother line .
My theory about haplogroup I is that it emerged in the aeria of Pamir in Tadjikistan from IJ and then gradualy moved toward the Europe . In Xingyang in China use to live nation of Yuezhi whose name is very similar to the name of Yazigi one of the Alan tribe, name Alan meen " one that live in stepes" .Today in Xingyang live Uygurs with 60% of R1a haplogroup and 33% of I haplogroup . That I from Pamir give Germanic I1 and I2b and Median I2a moving gradualy over Central Asia and mixing with R1a which one lived there.
There is story in Herodothus that Scythians were moved from they lands in Central Asia by Masagets in to the land of Chimmerians which is then given the name of Scythia . And Masagets and Tisagets are ancestors of Alans - later they conjoined and taked name Alan - one thet live in steppes .These movement of Masagets was probably in the same time like movement of Medes on Zagros and they were relatives .
Serbian and Croatian titles župan i ban are Iranian , Herodotus say that name of first ruler of Medes was Deyoka , acctualy that is a title dah yanka -lord of nation = župan.