That is what I stated. Read again, and all you did was write why I did in a different wording:
"There was a period of mixing which was for THOUSANDS OF YEARS, and the all of a sudden things stopped. This coincides with the time of northern india being invaded by Europeans and the caste system starting".
Indo-Aryan is another word for people form turkey, right next to the Caucasus mountains. If you look at the map these people could have easily went all throughout eastern, and northern Europe. They were not some secluded group who just happen to go south to india, and mix with them. This is one reason why the "horse theory" was developed. Here is something on Indo-Aryan, and what some call the origin of civilization. I can go deep with this on how whites began, and evolved but, all I'm going to get is arguing and twisting my words with that because that is REALLY deep. I'm probably wasting time with this because yall didn't even read a simple science article properly.
http://arevordi.blogspot.com/2005/12/indo-european-aryan-homeland-map-above.html
Indo-European 'Aryan' Homeland
The map below essentially revels the pre-historic route proto-Indo-European (Aryan) tribes took during their epic journey that began approximately six to eight thousand years ago. According to this well developed theory, Indo-European Armenians, Greeks and Persians essentially evolved from the remnants of those tribes that had stayed within the general vicinity of their origin. Many linguistics experts and archeologists are now coming to the conclusion that the Armenian Highlands is where the first Aryans emerged. It is the Armenian nation today that still remains within the epicenter of the birthplace of Aryanism. Note: Thracian Phrygians (also known as the Mushki) who are simply a component of the Armenian nation, essentially returned to the land of their origin when they re-entered the Armenian Highlands approximately 1,500-1,000 BC.
Maybe I should have worded it different since yall seem to not understand, even though the article says things in plain english. People who had the same DNA to what we call Europeans today, specifically the Y chromosome(the male chromosome), made their way into northern india, and the fact that it was mostly male coincides with the theory of the aryans invading northern eruope and imposing the caste system as we know it today, and making themselves be a part of the higher caste. And the mixing before the invasion was with southern, and northern, not just those with european dna, if at all. Did yall even read the study because these things were dealt with in the articles. There are even more articles showing the differences in the people.