What Lebrok said is expected. He is correct I agree with Garrick and Lebrok. Slavic expansions happened East-West-South. Ofcourse there is population replacement in Poland from ancient times. What needs to be understood by outsiders, Poland was not always where it is located now. There was event "WW2" displaced many Poles from their original conquered territory of 17th Century Polish Commonwealth, I am talking about places like Western Ukraine, Northern Romania, Moldova, Belarus, Lithuania, Latvia, etc all belong to Poland where Poles and others lived and thrived for centuries in all these places I have listed. This was Polish homeland. In late 18th century Poland was ripped apart literally by new powers Russia, Austro-Hungary, Prussia. My ancestors didn't move anywhere despite this new government, they remained in same place even through changed borders remained and kept the "Polish Tradition" even after they technically didn't have our own homeland until 1918 for over 100 years.
Garrick, Tomenable big reputation? His theory is faulty with I2A-DIN expanding from Polesian swamp marshes in Belarus. I might have misunderstood your statement so correct me if I am wrong, what does reputation have to do with reality, or in correct terms to this discussion the expansion of I2A-DIN? If you decide to dive into these forums you should know exactly what is being discussed and not just throw around misleading hypothesis because this is curving discussion in wrong direction, not mention offended to people of this genetic by throwing out there unfounded statements. I mean you will not see me on the R1B thread talking about hypothesis because that is not my cup of tea. My goal is not intimidate anyone on here, everyone has right voice opinion on here to help contribute the missing puzzle pieces of this elaborate genetics discussion we are having. All I'm saying is post with some care. Meaning talk about things you know about. And don't spam. Any knowledge is welcome and sure there will be disagreements as comes with this territory but we can make effort to be civil about instead of constant spamming.
Garrick, my next point is yes you are right Slavs emerged as a known group around 500 AD. In a historical writings context. At this point in time they had entire army that ravaged Balkans. These Slavs had been interbreeding for centuries prior to 500 AD, it takes generations to create army of humans. I really don't want joke Slavs were not poofed out of magic in 500 AD nor were they dropped from mysterious UFO at approximate location of Danube lol. They were in these areas long time before that and existed, lived and yes we Slavs as you Garrick have done excellent job explaining with references are some sort combination of the groups living around the Black Sea ( Thracians, Sarmatians, Bastarnae, etc ) what is exact combination? I don't know but I certainly can narrow down to certain groups that we are and I can weed out the the groups the we definitely aren't. Some proof can be found on gedmatch calculators when you look at my sample or any other strong Modern East European samples. Now, I have reason to believe some of the things about I2A-DIN due to the research and it simply being my own haplogroup which I have studied. I want to thank Garrick for your extensive posts about Bastarnae tribe. You have opened my eyes to some knowledge about this tribe helping put more pieces of puzzle together that's what we all here for I mean most of us lol. I must admit you are putting far too much interest issues like TMRCA, Slavs not being recorded in history until 6th Century being slippery terrain, I will say again Garrick we are mix of these tribes and these tribes are somewhat Slavic in ancient perspective. Slavs didn't show up with entire army in 500 AD, we were interbreeding for centuries and your always discussing this 2300 years old theory of I2A-DIN which we need to remember is still a "theory" not a solid proof yet. Even we take this theory for truth it makes sense with migrations of Sarmatians, Scythians around exact time of 2300 years that I2A-DIN emerged.