y-dna haplogroups are not exclusive to any popoulation so you can have original Slavs and original Illyrians, Thracians even Greeks with y-dna I2a, as it arose thousands of years before any nationality was born. What you can say is that I2a2 is restricted to Eastern Europeans and especially the Balkans so ancient Illyrians should have a lot of it, but they should have even more E-V13 and a lot of J2,R1b too. All modern nations near the area of Illyria (primalry Bosnia,Monte Negro,Croatia,Albania and secondly Greece and North Italy) have some Illyrian ancestry in them and it's not easy to prove who is who here after all. For example Greek Macedonians have 15% I2a2 which could be :
1. Pelasgian Greek ( pre-historic balkanic)
2. Thracian
3. Illyrian
4. Slavic
5. Albanian
But who knows really? I'll say it again haplogroups do not prove ancestry...
well lets see
Y-Dna has no language, that is truth,
But Y-Dna can help us find areas and movements of people,
if a myth, a report, an archaological evidence exists and can be connected time-line with that devastation, then you have your self a fact,
for example
Pelasgic people,
from the linguistic elements we find that they spoke a Middle East language,
pelasgic culrure is also found in City Of Avaris, and In Syria and Palaistine,
word simmilarity and archaiological evidence show Levant and Italy connection,
Now in that area I2a2 is very low and J" is Enough and ancient,
in Crete in areas were not mentioned as IE invaded we have also High J2,
the remarkable existance of J2 in both areas,
The remarkable small existance of I2 in one area
points that Pelasgic were mainly J Y-DNA dominant and not I2a2 .
By understanding that slowly you find or prove more,
As an example i Give that,
PAiones -Paeoni are mentioned as Thracians, Paeoni lived north of Gr Makedonia and around area of Serres,
according Myth Agrios and Endymion in Area of Agrinio was the Father of Paeon who later moved to Paeoni area,
we see Agrinio (Agrios) has high I YDNA population (almost dominant)
we see Serres has high I YDNA population,
now if secondary marks are connected then the myth is true,
and connects Agrinio with Serres,
Meaning that in Agrinio were Thracians, which for me Thracians unite with Pelasgic and create Greek culture, altough later devastasion happened, traces have been left,
As an example, In USA today have many Ydna, in some areas European Ydna are dominant today,
Does that mean that Indians were Europeans?
No way,
But by mutations and comparisons we find tribal Dominant and ancient Dna,
as an example of Pelasgic I send you to Gennesis in Bible,
'οι υιοι Ιαυαν κατωκησαν τας νησους τας εν Θαρσεις'
were it says Ionic people devastate to the islands in middle of Thracian
(Gennetic maps proves the above J2 in Aegean islands surounded By I2)
so Pelasgic were J2 and Thracian were I2,
now Illyros son of Cadmos, brother of Phoinix -(phoenician)
since cadmus was brother of Phoinix means Pelasgic the other Branch of J people
in Illyria (Albania) we found an Ancient J2b which is simmilar with Greek-Pelasgic,
and Pelasgic words,
the above connection of myth, historical, linguistic, and gennetic tell us that in Albania there is a pelasgic population
as an example I give the word
Erebos Gr Pelasgic
Erevet Alb Pelasgic
Erebu ancient phoenician and semetic
Besides it is another area
Illyrii proprie Dicti and another area
Illyricum
Croatia Bosna etc
about slavic people 'How yes no' has a qood post about their dominant Ydna,
altough I have my arquments in slavic language,
http://www.eupedia.com/forum/showthread.php?t=26341